Henk-Jan Boersema

The concept of inability to work fulltime in work disability benefit assessment Henk-Jan Boersema

The concept of inability to work fulltime in work disability benefit assessment Henk-Jan Boersema

Colophon This research was conducted within the Research Institute SHARE of the Graduate School of Medical Sciences, University Medical Center Groningen, University of Groningen and under auspices of the research program Public Health Research(PHR), at the Department of Health Sciences, Community and Occupational Medicine. This department participates in the Dutch Research Center for Insurance Medicine (KCVG), along with the Department of Public and Occupational Health, VUmc Amsterdam, the Department of Public and Occupational Health, AMC Amsterdam, and the Dutch Institute for Employee Benefits Schemes (UWV). The studies in this thesis were funded by the Dutch Institute for Employee Benefits Schemes (UWV). The printing of this thesis was financially supported by the Graduate School of Medical Sciences, Research Institute SHARE, University Medical Center Groningen, the University of Groningen. Cover design: Marcel Leuning Provided by thesis specialist Ridderprint, ridderprint.nl Printing: Ridderprint Layout and design: Jeroen Reith, persoonlijkproefschrift.nl ©2023 H.J.M. Boersema, the Netherlands All rights reserved. No part of this thesis may be reproduced or transmitted in any form or by any means without the prior written permission of the author.

The concept of inability to work fulltime in work disability benefit assessment Proefschrift ter verkrijging van de graad van doctor aan de Rijksuniversiteit Groningen op gezag van de rector magnificus prof. dr. ir. J.M.A. Scherpen en volgens besluit van het College voor Promoties. De openbare verdediging zal plaatsvinden op woensdag 29 november 2023 om 12.45 uur door Hindrik Jan Meerten Boersema geboren op 26 oktober 1956

Promotor Prof. dr. S. Brouwer Copromotores Dr. F.I. Abma Dr. T. Hoekstra Beoordelingscommissie Prof. dr. A.J. van der Beek Prof. dr. S.J. van der Burg - Vermeulen Prof. dr. C.A.M. Roelen

Paranimfen Koen Boersema Sibbe van der Molen

CONTENTS Chapter 1 General introduction 9 Chapter 2 Exploring the concept inability to work fulltime in the context of work disability assessments: a qualitative study 19 Chapter 3 The assessment of work endurance in disability evaluations across European countries 39 Chapter 4 Inability to work fulltime, prevalence and associated factors among applicants for work disability benefit 61 Chapter 5 Residual work capacity and (in)ability to work fulltime among a year cohort of cancer survivors who claim a disability benefit 85 Chapter 6 Residual work capacity and (in)ability to work fulltime among a year cohort of disability benefit applicants diagnosed with mental and behavioural disorders 109 Chapter 7 Inability to work fulltime and the association with paid employment one year after the work disability assessment: a longitudinal register based cohort study 133 Chapter 8 General discussion 155 Appendix Summary Samenvatting Dankwoord About the author Previous dissertations of SHARE 170 174 179 183 185

1 General introduction

10 Chapter 1 GENERAL INTRODUCTION Case study The central construct of this thesis is the ‘Inability to Work Fulltime’, assessed as part of the work disability benefit assessment. To illustrate the meaning of this construct I present a case from practice. A worker has been sick-listed from his work for almost two years, has not fully returned to his work, and applies at the social security institute for work disability benefits. He experiences serious problems in starting activities and taking initiative, is continuously tired, and needs to rest during the day. He has been diagnosed with a depressive episode and is undergoing psychiatric treatment. An insurance physician from the social security institute assesses the physical and mental impairments that limit his capacity to work. An important aspect of this assessment is the inability to work fulltime. The question for the insurance physician is how many hours per day and week this worker is able to work, and whether he is able to sustain working activities for normal fulltime working hours. The insurance physician knows that depressed people often suffer a lack of interest and drive, sleeping disturbances and fatigue, as well as mood disturbances, all of which interfere with normal daily functioning and make it unlikely that the depressed sick-listed worker will be able to work fulltime. However, it is complicated to estimate the number of hours this person can work. When the insurance physician consults the Dutch professional guideline, he finds insufficient information to support him in the decision-making process for this specific case. Consequently, he bases his decision on his own expertise and the available information. He hopes that he can make the right decision, knowing that the outcome of the assessment may have significant personal, social, and financial consequences for the employee. This case illustrates the importance and relevance of the assessment of inability to work fulltime, as well as the complexity of the construct. With the studies in this thesis, we aim to expand the knowledge regarding the concept inability to work fulltime, and how to apply this knowledge when assessing work disability benefits. In the following sections we describe the background and context of the study, and explain the research gaps and challenges related to the concept inability to work fulltime. Finally, we present our objectives and an overview of the thesis. Background Being able to work is central to quality of life, and is associated with multifaceted psychological, social, and economic benefits. Many countries recognize the importance of work, and strive to have their citizens participating fully in society, as besides financial necessity, work participation

11 General introduction also establishes identity and structure in everyday life [1-4]. This focus on work is reflected by the way current social security systems support people to stay at or return to (any) work, even partially or with adjustments [1, 5]. Over the last few decades, many industrialized countries have reformed their disability insurance programs to encourage work participation by long-term sick-listed employees who have residual work capacity (1). This shift in focus generally reflects the underlying idea that being able to work is a key to regaining health, economic self-sufficiency, and social standing [3, 6]. Although work participation is encouraged, people with chronic diseases have been found to have lower employment rates than people without chronic diseases. OECD reported in 2010 that employment rates of people with disabilities were low compared to those of people without disabilities. For example, in that period for all 27 OECD countries, employment rates were respectively 43% for workers with chronic diseases versus 75% without chronic diseases [1]. Moreover, in 2010 in the Netherlands nearly 25% of persons with chronic diseases worked 12 hours per week or more, compared with 67% of the total work force [7]. Persons with chronic diseases not only work less often [8], but on average they also work 9 hours per week less compared to the total work force [7]. Inability to Work Fulltime Inability to work fulltime literally means that a person cannot sustain working activities for normal fulltime working hours. Although this sounds clear, for physicians who have to decide whether a specific worker with a somatic or mental health condition is able to work fulltime is not easy. It depends on several factors, including non-medical ones. The ability of a person to be active in day-to-day working life is an important aspect of functioning at the level of the whole human being. The International Classification of Functioning and Health (ICF-model) describes functioning at three levels: body functions and structures, activities, and participation [9]. The factors influencing functioning are divided into three categories: health condition, personal factors, and environmental factors. Inability to work fulltime can be seen as a restriction in participation, an inability to work fulltime at any occupation, due to a combination of health-, personal-, and environmental factors. Being unable to work fulltime can have both a negative and, surprisingly, a positive impact on a person’s functioning in daily life (including work). For example, when people who are no longer able to work fulltime cannot fully re-integrate into their fulltime jobs, this can lead to involuntary loss of their jobs and (partial) work disability benefits. The employer may experience loss of productivity and expertise and face the extra costs of replacement. Society is also burdened with the extra costs of unemployment or work disability benefits. Nevertheless, in spite of the negative impact of being unable to 1

12 Chapter 1 work fulltime, being assessed with an inability to work fulltime and thus no longer obliged to pursue fulltime work participation, may also have a positive impact. It may release workers from the pressure of (looking for) a job with more working hours than they can cope with. Moreover, employers suffer less economic damage if workers are sick-listed for fewer than fulltime working hours, especially in a situation where there are many part-time positions available in the labour market and part-time employment is generally accepted as in the Netherlands [10]. A reduction of working hours may be helpful for people returning to or staying in the labour market. A Dutch study indicated that people unable to work fulltime nevertheless often have favorable work characteristics, such as a higher education and experience in previous employment [11]. These advantages make it easier for them to get a part-time job. In addition, a recent review described that changes in work times (and flexibility in time scheduling as work accommodation), had strong positive associations with return to work among workers on long-term sick leave and assessed with residual work capacity [12]. This may indicate that confirming sick-listed employees’ inability to work fulltime could positively affect their return to work. It could also allow them to continue to work part-time, while protected from income loss by disability benefits. However, research on this topic is lacking. Assessment of Inability to Work Fulltime In the Netherlands, the work disability benefit assessment is performed by insurance physicians from the Dutch Social Security Institute: the Institute for Employee Benefits Schemes (UWV) under the Work and Income Act (WIA) [13]. To assess the work disability benefit, these physicians use a (semi- ) structured interview to gather information on the applicant’s medical-, work-, and social situation, as well as his/her functioning. They also use other sources, such as treating- and occupational health physicians. In 2013, for example, 57.811 first assessments took place. Of these, 15.6% resulted in partial disability and 41.9% in full disability; 42.6% of the applications were rejected [14]. Assessment includes a ruling about an applicant’s (in)ability to work fulltime, reported as the number of hours he/she can work per day, graded in steps of 2 hours. In 2000 the professional guideline (in Dutch: ‘Standaard verminderde arbeidsduur’) was designed to support and guide insurance physicians when assessing inability to work fulltime and to improve the reliability and validity of these assessments [15]. However, due to a lack of scientific evidence, the professional guideline is based only on the expertise of these physicians. A group of insurance and occupational health physicians supervised the development of the guideline and reached consensus on three specific indications of inability to work fulltime: 1. a lack of energy consistent with

13 General introduction the diagnosis, 2. reduced availability for work due to necessary treatment, and 3. an indication that an increased number of working hours will impair a person’s functioning in private life and exacerbate his/her disease symptoms. In addition, these physicians concluded that combining data from the assessment interview with additional data – such as from tests like exercise tests and Functional Capacity Evaluations, findings from significant others, and information about the subject’s personal and social situation – is necessary for adequate assessment of the inability to work fulltime. Although this professional guideline may support physicians in their assessments, it is not an evidence-based practice guideline, as is mentioned above. In an opinion article in 2011, W.C. Otto, insurance physician, policy officer, and member of the guideline development group, summarized the views and problems experienced with assessment of inability to work fulltime, and reported that insurance physicians found it difficult to perform such assessments. Problems included questions regarding the number of working hours that should be considered normal, and whether non-medical factors should also be taken into account [16]. In 2001, in a study on inter- and intraassessor reliability, Spanjer reported among insurance physicians a large spread in outcomes of assessments [17]. In another study, Spanjer et al. described inadequate agreement among physicians concerning how to assess the number of hours a patient could function per day [18]. He concluded that ‘despite the existence of a Dutch Guidelines for Hours Limitations available for insurance physicians, there remains too much scope for subjective interpretation’. This indicates that physicians need to have a more precise understanding of what the concept entails, as well as insight into other, related, factors. Providing more evidence on this topic may help insurance physicians in their assessments, and also be beneficial for workers with disabling health conditions, as well as occupational health physicians, employers, and other stakeholders involved in the field of work disability. Objective and research questions The overall aim of this thesis is therefore to explore, conceptualize and operationalize inability to work fulltime in the context of work disability benefit assessments. More research into the concept of inability to work fulltime can help to bridge an important knowledge gap in insurance medicine and provide stepping stones toward establishing clear evidence regarding inability to work fulltime. 1

14 Chapter 1 This overall aim has been broken down into three research questions: 1. What does the concept inability to work fulltime entail, and how can this be measured? 2. What is the prevalence of inability to work fulltime and what are associated socio-demographic and disease-related factors? 3. What is the association between inability to work fulltime and having paid employment one year after the work disability benefit assessment? Setting The studies for this thesis were conducted within the Dutch social security system. Because a social security system strongly affects work disability benefits, it is important to understand the context in which the assessments are conducted. In the Netherlands, long-term sick-listed workers with a limited work capacity due to chronic disease may apply for work disability benefits to compensate for income loss after two years of sickness absence. During the first two years of sickness absence, employers are obliged to continue wage payment to their workers. They also share the responsibility to help their sick-listed workers to reintegrate. These employees can apply for work disability benefits at UWV, the Dutch Social Security Institute: the Institute for Employee Benefit Schemes. They may receive work disability benefits for a disease or handicap due either to occupational or non-occupational causes. An insurance physician and a labour expert together assess the (remaining) work capacity and eligibility for work disability benefits. The work disability benefit assessment includes a medical assessment of functional limitations by an insurance physician, and an assessment of earning capacity by a labour expert. Individuals may have either a full work disability or a partial work disability [19]. Those in the latter group have residual work capacity: they are considered able to continue working after the assessment, either partially or with work adjustments. These workers are encouraged to continue in paid (part-time) employment with their current employer, or enroll in a new, more appropriate, (part-time) job with their current-, or a new, employer. The income for the original work before sick leave is compared with the income for the work they can perform according to their residual work capacity. The amount of income loss determines the amount of the work disability benefit, with a threshold of 35% loss of income. For an income loss of less than 35%, no financial compensation is provided. UWV stores data from all work disability benefit assessments, including the outcome inability to work fulltime, and data on the work status of the entire Dutch population, in separate registers. These data are thus an important source of information for research.

15 General introduction Outline of the thesis This first chapter (Chapter 1) is a general introduction, describing the societal background of the concept of inability to work fulltime, placing this concept in the setting of work disability benefits, and laying out the research gaps and aims of the thesis. Chapter 2 presents the findings of an interview study involving perspectives of both patients and physicians, to provide a conceptualization and operationalization of the concept inability to work fulltime as well as an inventory of assessment methods. Chapter 3 presents findings from a survey across experts from 19 countries, through the European Union of Medicine in Assurance and Social Security (EUMASS), to explore the characteristics and the assessment of inability to work fulltime across European countries. Chapter 4 presents descriptive data on various aspects of (the assessment of) inability to work fulltime. It also provides information about the prevalence and degree of inability to work fulltime in the Netherlands, and describes relevant socio-demographic and diseaserelated factors. For this study we used a cross-sectional register-based cohort of applicants for long-term work disability benefits, according to the Work and Income Act (WIA) [13]. Chapters 5 and 6 explore the prevalence, and associations with our subject, in applicants diagnosed with cancer (Chapter 5) and mental health problems (Chapter 6), using the same cohort. Again, using the same cohort, Chapter 7 presents results of a study to explore the association of inability to work fulltime with having paid employment one year after the assessment, using follow-up register data on work participation. Chapter 8, the general discussion, presents an overview of the main findings and discusses the results. It also provides implications for policy and practice, and recommendations for future research. 1

16 Chapter 1 REFERENCES 1. OECD. Sickness, disability and work: breaking the barriers. Paris: OECD; 2010. 2. Rasmussen DM, Elverdam B. The meaning of work and working life after cancer: an interview study. Psychooncology. 2008;17(12):1232-8. 3. Waddell G, Burton AK. Is work good for your health and well-being? 2006. 4. Saunders SL, Nedelec B. What work means to people with work disability: a scoping review. J Occup Rehabil. 2014;24(1):100-10. 5. Sengers JH, Abma FI, Wilming L, Roelofs PD, Heerkens YF, Brouwer S. Content validation of a practice-based work capacity assessment instrument using ICF core sets. J Occup Rehabil. 2021;31(2):293-315. 6. Schuring M, Mackenbach J, Voorham T, Burdorf A. The effect of re-employment on perceived health. J Epidemiol Community Health. 2011;65(7):639-44. 7. Maurits E, Rijken M, Friele R. Kennissynthese ‘Chronisch ziek en werk’: arbeidsparticipatie door mensen met een chronische ziekte of lichamelijke beperking (Knowledge synthesis ‘Chronically ill and work’: work participation by people with chronic illness or physical disability). Utrecht: NIVEL; 2013. 8. van Zeijl J, Mateboer M, Prevost C, Pronk R, Voorrips L, Witvliet C. Meting IVRPHindicatoren 2020 - Indicatoren ten behoeve van de monitoring van het VN-verdrag handicap. CBS; 2022. 9. WHO. International classification of functioning, disability and health: ICF: World Health Organization; 2001. 10. OECD. Part-time employment rate. 2018. Available from: https://www.oecd-ilibrary. org/content/data/f2ad596c-en. 11. APE. Verdiepingsonderzoek WGA 80-100 (in depth study full work disabled). 2015. Available from: https://www.rijksoverheid.nl/documenten/rapporten/2015/07/08/ verdiepingsonderzoek-wga-80-100. 12. Jansen J, van Ooijen R, Koning P, Boot CR, Brouwer S. The role of the employer in supporting work participation of workers with disabilities: a systematic literature review using an interdisciplinary approach. Journal of Occupational Rehabilitation. 2021;31(4):916-49. 13. Netherlands Government. Wet werk en inkomen naar arbeidsvermogen (Work and Income Act). 2005. Available from: https://wetten.overheid.nl/BWBR0019057/202003-19. 14. UWV. UWV Jaarverslag 2013 (Annual report 2013, the Institute for Employee Benefit Schemes in the Netherlands). Amsterdam; 2014 March 14 2014. 15. Lisv. Standaard Verminderde Arbeidsduur (Guideline reduced working hours). 2000. Available from: https://www.arbeidsdeskundigen.nl/kennis/overzicht/richtlijnen. 16. Otto WC. Urenbeperking wat is de norm? (Working hours limitation: what is normal?). TBV. 2011;19(10):462-7. 17. Spanjer J. De inter- en intra-beoordelaarsbetrouwbaarheid van WAO-beoordelingen (The inter- and intra-rater reliability of disability pension assessments). TBV. 2001;8(9):234-41. 18. Spanjer J, Krol B, Brouwer S, Groothoff J. Inter-rater reliability in disability assessment based on a semi-structured interview report. Disabil Rehabil. 2008;30(24):1885-90. 19. Koning P, Lindeboom M. The rise and fall of disability insurance enrollment in the Netherlands. J Econ Perspect. 2015;29(2):151-72.

17 General introduction 1

2 Exploring the concept inability to work fulltime in the context of work disability assessments: a qualitative study Henk-Jan Boersema Femke I Abma Tialda Hoekstra Pepijn DDM Roelofs Sandra Brouwer BMC Public Health. 2021;21(1):1-10.

20 Chapter 2 ABSTRACT Background: In many countries inability to work fulltime is recognized as an important concept in work disability assessments. However, consensus is lacking regarding the concept and how it should be assessed. This study seeks to conceptualize and operationalize the concept of inability to work fulltime, and includes perspectives of both patients and physicians. Research questions involve identifying: 1. key elements, 2. measurable indicators, and 3. valid methods for assessing indicators of inability to work fulltime. Methods: We used a qualitative study with a thematic content analysis design to conceptualize inability to work fulltime, based on nineteen semi-structured interviews conducted among insurance and occupational health physicians, and representatives of patient organizations. Results: Inability to work fulltime is conceptualized as a complex concept which is strongly individually determined and variable due to time and underlying disease. Key dimensions of inability to work fulltime included besides the disease itself, also personal factors like psychological and lifestyle factors, as well as environmental factors related to the work situation and social context. Fatigue, cognitive impairments, and restrictions in functioning in- and outside work were reported as important measurable indicators. A combined use of self-assessment, assessment interviews, and testing, and assessment in the actual (work) setting was identified for assessing these indicators. Conclusion: Taking into account the complex and variable nature of inability to work fulltime, we found it advisable to use multiple methods and multiple time points for the assessment. Results of this study provide starting points for further research on the operationalization of inability to work fulltime in a work disability context.

21 Exploring the concept inability to work fulltime in the context of work disability assessments INTRODUCTION Social security systems generally distinguish two main aims of work disability assessment: to decide about eligibility for disability benefits, and to determine what people are still able to do regarding work [1]. Included in work disability assessment is evaluation of whether a person is (un)able to work fulltime, i.e., whether or not employment participation is partially limited due to a health problem. As being able to work is vital for a person’s economic self-sufficiency and social standing, valid assessment is of great importance. In many European countries, inability to work fulltime is recognized as an important concept in work disability assessments [2]; the concept includes the restricted number of hours per day or week a claimant is able to work due to a chronic disease and/or other accepted causes. A previous study comparing 16 European countries showed that a majority of them included assessment of inability to work fulltime (or restricted work endurance) as part of the work disability assessment [2]. If a person is not able to work fulltime it can be described as an inability to work fulltime. Across countries, the definition of fulltime ranged from 35 to 42 h per week [2]. Both physical and mental disorders are accepted causes of inability to work fulltime, with the most often mentioned causes being musculoskeletal diseases, mental disorders, and diseases of the circulatory system. Limited research indicates that in most countries a general deficit in energy was the most frequent indication for granting a limited work endurance [2]. The few existing studies that assess the hours a person is able to work demonstrate confusion regarding the meaning of the concept inability to work fulltime [2, 3]. First, in different countries the concept is assessed differently [2]; various methods are used to aid in assessment, the most common being clinical tests, functional capacity evaluations, and psychological tests. Second, high inter-doctor disagreements have been found on the outcome of assessing inability to work fulltime, questioning the credibility of the current assessment procedures [4–6]. In a previous study we found that, although 10 out of 13 countries use formal rules to assess inability to work, in the Netherlands only a professional guideline is used [2]. This guideline [7] describes the ability to work fulltime as the ability to work at least eight hours per day. The inconsistencies found between countries and physicians may be due to the lack of evidence-based guidelines, and of reliable and valid methods for assessing a person’s (in)ability to work fulltime, but are first and foremost due to the lack of a comprehensive conceptualization and operationalization of the concept. Conceptualization involves formulation of clear and concise definitions: identifying the key elements, using characteristics (non-measurable key elements) and dimensions (measurable key elements). Conceptualization is followed by operationalization: making an abstract concept measurable by 2

22 Chapter 2 describing its dimensions and translating these into measurable indicators [8]. Effective conceptualizing and operationalization of the concept inability to work fulltime will thus shed light on its key elements and measurable indicators. This insight can then be used to develop methods for its assessment. This study seeks insight regarding conceptualization and operationalization of the concept of inability to work fulltime, based, among other things, on the perspectives of both patients and physicians. To assess the concept effectively, we also want to explore its dimensions and indicators. Our specific research questions are: 1) What are the key elements (characteristics and dimensions) of inability to work fulltime?; 2) What are measurable indicators of inability to work fulltime?; and 3) Which methods can be used to assess the measurable indicators of inability to work fulltime? METHODS Study design For our study, we used qualitative interviews to explore the concept of inability to work fulltime. Qualitative research is useful for understanding complex issues, explaining people’s beliefs and behaviours, and identifying social or cultural norms [9]. To evaluate the collected data we used thematic analysis, applying elements of both phenomenology and the grounded theory approach to content analysis to conceptualize and operationalize the concept. Dutch law required no ethical approval for this study, as participants were not subject to any intervention. All participants provided informed consent to record the interviews and publish the results, given that data were anonymized and untraceable to individuals. Participation in the study was voluntary, and participants received no incentive for participation. Participants We explored the concept inability to work fulltime from the perspectives of both the patient and the physician in order to triangulate points of view from these two main stakeholders. We invited physicians in staff and/or management positions in insurance and occupational medicine and in both public and private disability insurance, preferably with practical experience and with adequate knowledge of work disability assessment at scientific or staff levels. For the patients’ perspective, we invited representatives, expert staff members of patient organizations in the Netherlands, to participate. Patient organizations provide information, offer fellow sufferers contact, promote interests, organize activities, and support groups of specific patients not only with healthcare issues but also regarding social and employment participation. A patient organization is often established for and by patients. We purposively sampled patient representatives to include the major disease groups related to work disability

23 Exploring the concept inability to work fulltime in the context of work disability assessments (mental problems, neoplasms, and respiratory, nervous, and urogenital diseases), and to examine their experiences with the (in)ability to work fulltime. The researchers invited physicians from their own professional networks, and contacted most patient representatives through the websites of their organizations, or their professional networks. The authors approached participants by email and telephone to describe their own role, as well as the aim and context of the study. Data collection, interview content and procedure Between January and September of 2014, we conducted semi-structured interviews using open-ended questions. We developed an interview guide with topics and open-ended questions to aid the interviewers and to ensure comparability of the interviews, thereby increasing reliability. We tested this script with three insurance physicians, recruited from the researcher’s own network. Based on these try-out interviews the interview guide was finetuned, using more open questions. We chose to interview physicians and patient representatives to acquire data on (the assessment of) inability to work fulltime from the perspective of the key participants in the disability assessment interview. The final interview guide addressed the following major topics: 1) the concept of inability to work fulltime and its characteristics; 2) dimensions of inability to work fulltime; 3) indicators for measuring the dimensions of inability to work fulltime (signs and symptoms of the concept and its dimensions); and 4) methods to assess indicators of inability to work fulltime. Subtopics included: what is ‘normal ability to work fulltime’, or the maximum number of hours a person can work; disease specific aspects related to variability of inability to work fulltime; the best method to assess indicators of inability to work fulltime; and experience with assessing inability to work fulltime. To explore these topics more deeply, we asked further clarifying questions. Of the 19 interviews, 18 were conducted by two interviewers (HJB and senior researcher and insurance physician BC or research assistant JS [more information about the research team members can be found under Acknowledgements]); one interview was conducted by the first author only (HJB). We conducted all interviews in the participants’ first language (Dutch), during single sessions of 45–90 min; all were audio-recorded. We made no additional field notes. We interviewed most participants at their own preferred locations, and two by telephone; no other persons were present during the interviews. We transcribed all interviews verbatim. We did not present transcriptions to the participants for their comments, but presented and discussed our interpretations of the data at professional meetings with researchers, professionals, and policymakers in the field of work and health. 2

24 Chapter 2 Data analysis The first author verified all transcripts. We used thematic analysis to analyse the collected data [10]. We used an inductive approach to analyse the data, starting with line-by-line coding of the transcripts, using Atlas-ti (version 7.5.18) computer software. During this open coding process, we developed an initial list with codes. All data were coded by the main researcher, HJB, and two members of the research team (BC and FA), and codes were ultimately grouped and combined into subthemes in an iterative manner. We held weekly meetings to discuss disagreements in the coding and grouping processes, until reaching consensus. The last stage consisted of discussions among members of the research team (HJB, BC, FA, SB, PR, TH) until consensus was reached on the final themes. Data saturation was not the aim of this study, as we wanted to explore themes among representatives from major disease groups. All members of the research team work at the University Medical Center Groningen and are affiliated with the Research Center for Insurance Medicine. The first author, HJB, is an insurance physician and PhD candidate; FA has a background in work and organizational psychology; TH and SB have backgrounds in health sciences; and PR has a background in health sciences and occupational physiotherapy. FA, PR and SB have PhDs in the domain of work and health research, and are experienced in conducting qualitative research. Additionally, BC, who played an important role in analyzing the data, was an insurance physician and a senior researcher at the Research Center for Insurance Medicine, with a PhD in work and health. The mixed backgrounds of the team members enriched the analysis by introducing different perspectives. Analyses were influenced by the first author’s experience in conducting actual work disability assessments, and his extensive knowledge on the topic inability to work fulltime. We summarized and searched the texts underlying the themes and codes to find quotes that best illustrate the views and experiences of the interviewees. Quotes from interviewees were selected by two authors (HJB, FA), translated into English by a professional translator, and discussed with all co-authors. To indicate the diversity of opinions while maintaining anonymity, we indicate quotes from physicians with Ph1-Ph10, and from patient representatives with Pa1-Pa9. In the final iteration, we formed a conceptualization based on emerging themes describing the key elements. We used these key elements to operationalize the concept into relevant characteristics, dimensions and measurable indicators, and inventory methods for assessing these indicators. Although the interview guide contained no questions regarding the International Classification of Functioning, Disability and Health (ICF) [11], we were able to identify and categorize responses to this framework. Other sources of categorization were national guidelines on prescribing adequate,

25 Exploring the concept inability to work fulltime in the context of work disability assessments and/or reducing, working hours [7, 12]. Within the research team we discussed characteristics, dimensions and indicators to compose an overview of the concept inability to work fulltime. RESULTS Participant characteristics We initially invited 33 persons (13 physicians and 20 patient representatives) for interviews, 19 of whom (ten physicians and nine representatives of patient organizations) agreed to participate. Reasons for refraining from participation varied: lack of time, illness, insufficient expertise, or the topic or interview did not fit with the scope of the organization. In our final group, seven out of ten physicians were insurance physicians: four working in public disability insurance (Ph1–4), and three working in private disability insurance (Ph5–7). Three participants were occupational health physicians (Ph8–10). Nine physicians were male, and five had obtained a PhD-degree. The nine staff members from patient organizations represented patients with five disabling chronic diseases (mental and behavioral conditions (n = 3) Pa1–3, diseases of the nervous system (n = 3) Pa4–6, genitourinary system disorders (n = 1) Pa7, neoplasms (n = 1) Pa8, and diseases of the respiratory system (n = 1) Pa9). All subjects had received higher education, most at university level; six were female. All worked as project manager, (senior) staff member, or advisor. Main findings Overall, findings from the two stakeholder groups corresponded, with only a slight difference in point of view on inability to work fulltime. In the interviews, discussion of the key elements (dimensions and characteristics), the measurable indicators, and the related assessment methods was intertwined. An overview of the terminology and main findings is presented in Table 1. Patient representatives tended to describe the inability to work fulltime from a more holistic perspective, while physicians, and especially insurance physicians, used a more narrow bio-medical perspective. 2

26 Chapter 2 Table 1 Conceptualization and operationalization of the concept ‘inability to work full time’ Conceptualization (identifying key elements) Characteristics Inability to work normal working hours Variability of inability to work fulltime: - due to time - due to underlying disease Dimensions Disease and personal factors (i.e. psychological and lifestyle factors) Environmental factors (i.e. work-related and social factors, and norms) Operationalization (measurable indicators) Indicators Fatigue Cognitive impairments Restrictions in functioning in- and outside work Assessment methods Self-assessment Assessment interviews Functional testing Assessment in the actual work setting Conceptualization of inability to work fulltime Characteristics of inability to work fulltime Most participants found inability to work fulltime a complex concept to operationalize. It describes the inability of a person to work normal working hours, i.e. not able to work a normal number of hours per day and per week. Important characteristics of inability to work fulltime are that it is strongly individually determined and is variable. One patient representative stated when asked; “What do you consider a normal work-time capacity?”: “that, of course, varies from person to person” Pa8). A physician stated: “the work capacity, that is different for each person” (Ph7). Additionally, two aspects were described characterizing the variable nature of inability to work fulltime: variability due to time, and variability due to the underlying disease. Variability due to time. Inability to work fulltime varies over time due to many different factors. As one physician stated: “We are not machines. We are influenced by all sorts of things happening in and outside ourselves over time. That varies all the time” (Ph3). Another physician stated: “When you’re talking about work ability in terms of a social norm, I think it varies over time. Nowadays we expect other things from people than twenty years ago” (Ph1).

27 Exploring the concept inability to work fulltime in the context of work disability assessments Both physicians and patient representatives mentioned that with age, people have a reduced capacity to bear physical and cognitive strain, need more recovery time, and are less resilient. However, physicians also described a learning curve over time, involving the development of more (cognitive) skills that may compensate for this reduced physical capacity; as one physician stated: “The physical capacities may decline somewhat over the years, but you can make up for that with things like increased skills” (Ph7). Variability due to underlying disease. Participants mentioned that variation in severity and complaints, the effect of treatment and training, and personal and external factors may affect a person’s ability to work fulltime. The type of disease was often mentioned as a variable factor related to, and a potential indicator of, the impaired ability to perform working activities; examples were severe heart failure and chronic renal insufficiency. However, they stressed that not only having the disease (the diagnosis) itself causes inability to work fulltime, but also the course of the disease. Physicians remarked, “Even some people with depression are able to work” (Ph1), and “We all know that a well-known feature of all kinds of depressive disorders is that they fluctuate” (Ph3). Additionally, most participants mentioned treatment and rehabilitation as factors influencing the number of hours a person can work. For example, cancer treatments and time-consuming kidney dialyses were mentioned as significant barriers to being able to work fulltime. However, cancer rehabilitation, sports, cognitive training, and stepwise functional recovery were mentioned as factors that positively influence inability to work fulltime, regardless of the person’s diagnosis. A physician stated: “Well, work ability varies with the clinical picture, the health condition, whether the condition is active, and whether there are treatment options now or in the future” (Ph2). Dimensions of inability to work fulltime Disease and personal factors. Besides the type of disease, several personal factors were mentioned as key dimensions of the inability to work fulltime. Physicians reported further psychological factors, such as a person’s (in)ability to cope, as well as motivations and orientation in life, as important aspects that influence the number of hours a person can work. Patient representatives mentioned an improved lifestyle (e.g., smoking cessation, more exercise), positive orientation and goals in life, the choice to work self-employed, having self-confidence, and coping with the disease to be of influence. One physician said: “Some people just get hung up on it; others don’t” (Ph3). One patient representative stated: “Some people just want to achieve a higher ability to work because it has to do with certain personal life goals” (Pa9). 2

28 Chapter 2 Environmental factors. As environmental factors, physicians mentioned work-related factors (e.g., workload, work content, work autonomy, commuting time) and workplace factors (e.g., facilities, noise, light, climate). Patient representatives added organizational policies and practices, social support, job control and job fit, conflicts at work, discrimination, and re-organization as factors associated with the ability to work fulltime. One physician said, “The moment you create more possibilities at work, people have the ability to make a positive contribution to work, even at higher ages” (Ph9). A patient representative said, “All circumstances at work, and whether or not you are satisfied with them, play a very important role in your work capacity” (Pa2). Regarding social factors, we found that workers’ social situations can impact the number of hours they are able to work. A person’s household, family obligations, family concerns, problems and worries, may negatively influence the ability to work a certain number of hours per day or per week. However, family support can also have a positive effect. A physician said, “When you have big problems in your private life, you can be physically able to work, but your true ability to work and your productivity will be lower as long as these issues are not resolved” (Ph9). A patient representative said, “When you have a good partner, good support and feel well, you are better able to cope with your limitations” (Pa6). Further, most participants stated that societal norms strongly influence what is generally considered to be normal. Both physicians and patient representatives considered fulltime working as normal, but the number of hours per day and per week may differ, depending on societal norms. These norms can be based on legal and collective arrangements between employers and employees regarding working conditions, on policies within companies, and on insights within social groups. A physician said, “What is expected of a worker is based on legal or social norms. Apparently, a Dutch fulltime employee is legally required to work 40 or 38 hours, depending on the labor agreement, or fewer hours, depending on the employment contract. But that doesn’t say anything about his physical ability” (Ph5). A patient representative said, “I think that most people are able to work between 30 to 40/50 hours (per week), but it strongly depends on where you come from and on your upbringing” (Pa3). Participants generally agreed that every person has his or her own maximum of hours that he/she can work, and stated that it is impossible to prescribe a universal maximum of working hours. A patient representative stated, “I think the maximum amount is very personal and very much dependent on the sort of work you do. I don’t think there is an upper limit that applies to everyone” (Pa8). Physicians stated that the maximal number of hours a person can work per day or per week may differ from person to person, ranging from 9 to 12 h per day and from 55 to 80 h per week. According to the physicians, the upper limit is influenced not only

29 Exploring the concept inability to work fulltime in the context of work disability assessments by health status, but also by personal factors (physiology, coping abilities, motivation, training), and environmental factors (individual workload, safety requirements, home situation). Frequently exceeding one’s maximum may lead to long-term health complaints and negative health effects, indicating a need to recover from physical and mental work efforts for a shorter or longer period of time. A physician stated, “Research shows that people make more mistakes, get tired and have more problems concentrating if they work longer than nine consecutive hours without a break” (Ph9). A patient representative said, “In earlier days, and nowadays in some countries, people worked from sunrise to sunset, and then went to sleep. That’s exhausting, and that’s why these people didn’t get very old” (Pa3). Operationalization of inability to work fulltime into measurable indicators Indicators of inability to work fulltime We found three relevant measurable indicators to assess inability to work fulltime: fatigue, cognitive impairments, and problems in functioning in- and outside work. Patient representatives of patients with somatic diseases mentioned more physical indicators (“slow recovery”, “specific disease-related complaints like pain and dyspnea”) while those representing patients with mental disease mentioned more cognitive indicators (“execution of complex tasks”, “overview of situations”, “coping with emotions”, and “environmental stimuli”). Fatigue. Fatigue was reported as an important indicator of inability to work fulltime. Patient representatives stated that people with inability to work fulltime “lack the energy” (Pa8, Pa1, Pa7), and “run into all kinds of barriers” (Pa8, Pa4). Physicians stated that these people “feel unable to work the whole day” (Ph8), that “they can’t accomplish anything anymore after six hours of work” (Ph8). Cognitive impairments. Physicians stated that people with inability to work fulltime “can’t cope any longer” (with a full day’s work) (Ph5), that they “need more time to understand things” (Ph2). Participants also mentioned that people with inability to work fulltime have problems with cognitive and complex tasks, stating that they “forget” (Pa7), “make mistakes” (Ph1, Ph2, Ph4, Ph10), “have no overview” (Pa4, Pa2, Pa3), and “have fewer problemsolving abilities” (Pa5). Some also mentioned emotional complaints as indicators of inability to work fulltime, such as “irritability” (Pa4, Pa5), “less able to cope with conflicts” (Pa4), and “mental decompensation” (Pa5). 2

30 Chapter 2 Restrictions in functioning in- and outside work. Most participants reported that people who cannot work fulltime have problems with functioning both in- and outside work. They emphasized the importance of having sufficient time to recover from work, and balancing work with other activities like household tasks, self-care, and social activities. For example “doing less” (Ph6), “needing a power nap” (Ph9), “being unable to do anything in the evening hours after work” (Ph3), “not being able to get out of bed” (Ph7), “going to sleep during the day” (Pa4, Pa3), “[making] mistakes in their work” (Ph9), “function[ing] less well at work when they continue to work longer” (Ph2), “[being unable to] visit friends anymore in the evening” (Pa7), and “not [being] able to go out anymore or do sports” (Pa4). Assessment methods of inability to work fulltime Quantifying the number of hours per day a person can work is seen as an enormous challenge. As one physician indicated, “It is relatively easy to determine that someone is unable to work fulltime, but when it comes to assessing the level of inability to work fulltime we are just swimming” (Ph4). After we explored how best to assess the indicators of inability to work fulltime four methods emerged: self-assessment, assessment interviews, functional testing (e.g., Functional Capacity Evaluation (FCE), psychological tests and ergometry [e.g., exertion test and VO2max-determination]), and assessment in the actual work setting. Although there was no consensus about a single best method, most participants found it insufficient to use only one instrument. Self-assessment methods alone were not regarded as a suitable measure. Patient representatives pointed out that “people with certain disorders, like depression, may have trouble realizing their own limitations” (Pa1). Physicians also stated that a client’s own estimation of functional impairments, activity limitations, and participation restrictions may need to be complemented with additional information, such as that provided by a semi-structured assessment interview. Although most physicians considered an assessment interview to be an important method, especially in combination with other methods, patient representatives found such interviews invalid. They considered the method too simplistic; as one patient representative (Pa3) stated, “the simple conversation at the social security institute doesn’t work”. They declared that the assessment interview should also include “examples of functioning and daily activities, information from treating physicians, and checking for inconsistencies” (Ph5), as well as “recovery after exertion, the personality of the client, and the psychosocial situation” (Pa7), and could be supplemented with “speaking with people next to clients, like significant others, employers or mentors” (Pa3), and gathering “information about what happened before, in the first two years of sick leave” (Pa4).