COMPLETION RATES IN HEALTH-RELATED QUALITY-OF-LIFE ASSESSMENT - APPROACH OF THE NATIONAL-CANCER-INSTITUTE OF CANADA CLINICAL-TRIALS GROUP

The approach of the National Cancer Institute of Canada Clinical Trial s Group to measuring compliance, that is, completion rates, for health -related quality of life questionnaires is presented. Completion rates can be measured at the institutional, patient, questionnaire and item levels for baseline, on-treatment and off-treatment follow-up study p eriods. Time windows are defined for each expected completion time. In seven completed clinical trials, completion rates were high with more than 93 per cent of patients completing questionnaires in the specifi ed time windows at baseline and while on-treatment. The rate while on off-treatment follow-up is still acceptable at 85 per cent. The propor tions of analysable questionnaires were 97.6 per cent, 82.0 per cent a nd 77.0 per cent respectively, at the three study periods. Item comple tion rates within questionnaires were high at 95.5 per cent or more. T he variables most likely to influence baseline and on-treatment questi onnaire completion rates were breast cancer, ovarian cancer, metastase s and study centre size. (C) 1998 John Wiley & Sons, Ltd.