Maarten van Egmond

25 Preoperative functional status and postoperative complications 2 ICF: Body functions We measured IMS with a micro-medical spirometer (Micro-RPM, Micro Medical Ltd., Rochester, England), which measures maximal inspiratory pressure (MIP) as indicator of IMS and has been shown valid and reliable in surgical populations. 2,15 We calculated the percentage IMS of predicted by using normative values for Caucasian adults, predicted by a regression equation based on age and height. 19 We used the Jamar ® grip strength dynamometer (Lafayette Instrument Company, Lafayette, USA) to measure HGS. This dynamometer is a reliable instrument to predict the total skeletal muscle strength. 15,20-22 We calculated the percentage HGS by using normative values for adults. 23 ICF: Activities and participation We measured daily activities with the Longitudinal Ageing Study Amsterdam (LASA) Physical Activity Questionnaire (LAPAQ), in which patients reported their activities of the past 14 days. The LAPAQ is a face-to-face questionnaire that is highly correlated with both the 7-day diary ( r = 0.68, P < .001) and moderately to the pedometer ( r = 0.56, P < .001), whereas the repeatability is reported as reasonably good (weighted Kappa: 0.65 to 0.75). The LAPAQ appears to be valid and reliable in measuring activities in older people. 15,24 In addition, patients completed the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30, (EORTC QLQ-C30), version 3.0 to indicate HRQL. This is a nine multi-item scale including five functional scales (physical, role, cognitive, emotional, and social); three symptom scales (fatigue, pain, nausea and vomiting); and a global health and quality-of-life scale. Scores range from 0 to 100 with high scores indicating a better HRQL. It is a reliable and valid measurement of the quality of life of patients with cancer in multicultural clinical research settings. 25 To guarantee optimal inter-rater reliability, we described standardized operating procedures of all measurements. Experienced physiotherapists with extensive clinical expertise executed the standardized measurement protocol and all received an in-depth training of the study protocol, the standardized measures as well as data registration according to ‘Good Clinical Practice’. Outcome measurement The presence of POC was the outcome measurement of interest. All complications and adverse events within 30 days of surgery or during the in-hospital stay after surgery have been included, as proposed by the Esophagectomy Complications Consensus Group (ECCG). 26 We classified the severity of POC according to the widely used Clavien-Dindo classification