Measurement of disability-free survival and other patient-centred outcome measures in a surgical population

This thesis focuses on the patient-centred outcome measure of disability, as measured by the World Health Organization Disability Assessment Schedule 2.0 (WHODAS). I confirmed that WHODAS is a valid, reliable, responsive and acceptable measure of disability in a surgical population, and estimated the WHODAS scale values that define the minimal clinically important difference, patient acceptable symptom state and clinically significant disability. The remainder of the thesis concerns the ability of exercise testing and other assessments of functional capacity to predict disability after surgery in various surgical populations. A point-score model was developed to predict postoperative disability-free survival in the elderly.