Chapter 6 176 the study between May 2020 and June 2021 within 7 days after diagnosis or hospital admission. A small proportion of hospitalised participants were enrolled retrospectively to ensure representation of patients hospitalised during the first wave of COVID-19 in the Netherlands. Further details of study design and population have been outlined previously[9]. Briefly, eligibility criteria included laboratory confirmation of SARS-CoV-2 infection by reverse transcriptase polymerase chain reaction (RT-PCR), age 16-85 years, residing in the municipal region of Amsterdam, and adequate understanding of Dutch or English. Individuals residing in a nursing home and those with mental disorders deemed likely to interfere with adherence to study procedures were excluded. RECoVERED was approved by the medical ethical review board of the Amsterdam University Medical Centres (NL73759.018.20). All participants provided written informed consent. Study procedures and outcome assessment Socio-demographic characteristics, physical measurements and medical history were recorded through standardised interviews conducted by trained staff during the first month of follow-up. Participants reported symptom presence, severity and start/stop dates at day 0 (D0) , day 7 (D7) and month 1 (M1) of follow-up for 20 different COVID-19 symptoms[10]. Participants then completed monthly standardised online questionnaires on the presence (in the preceding month) of these same 20 symptoms from M2-M12 and at M18 and M24 of follow-up. Finally, the validated Brief Illness Perception Questionnaire (B-IPQ)[11, 12], which measures modalities of response to illness, was completed at M1, M6, and M12 of follow-up. For the current analysis, we included RECoVERED participants with at least one completed symptom questionnaire, and used data collected until 1 November 2022. Definitions Illness onset was defined as the earliest date upon which COVID-19 symptoms were reported. WHO definitions for long COVID and acute COVID-19 severity are noted in Supplementary Materials. BMI was defined in kg/m2 as: <25, underweight or normal weight; 25-29, overweight; ≥30, obese. The B-IPQ[11] was expressed both as a total score (continuous variable with no validated cut-off values) and as sub-scores for each domain: consequence/influence, timeline, personal control, treatment control, identity, concern, comprehension and emotions. Higher B-IPQ scores denote a more negative illness perception whilst lower scores indicate a more benign illness perception. Hypothesizing
RkJQdWJsaXNoZXIy MTk4NDMw