The Quality of Working Life Questionnaire for Cancer Survivors: Sufficient responsiveness for use as a patient-reported outcome measurement

Abstract

To assess the responsiveness and interpretability of the Quality of Working Life Questionnaire for Cancer Survivors (QWLQ-CS). A cohort study was conducted in which 130 (self-)employed cancer survivors completed the QWLQ-CS at baseline and 107 at follow-up and six single-item external anchors to measure change. Cancer survivors were diagnosed between 3 months and 10 years previously. To measure responsiveness we assessed the Area Under the Curve (AUC) of Receiver Operation Characteristic (ROC). To assess interpretability we compared Minimal Important Change (MIC) to Smallest Detectable Change at group level (SDC_group). The MIC was based on the mean change method and the SDC on the measurement error. We found sufficient responsiveness for improvement with AUC of 0.72 and sufficient interpretability with MIC (3.9) exceeding the SDC_group (2.8). Accordingly, we found sufficient responsiveness for deterioration with AUC of 0.27 and sufficient interpretability with MIC (-7.4) exceeding SDC_group (2.8). An improvement of 3.9 on the QWLQ-CS is meaningful to cancer survivors as is a deterioration of -7.4, both of which can be reliably measured at group level. The QWLQ-CS can be used as a patient-reported outcome measurement (PROM) of an intervention in research or practice at group level.

Keywords: cancer survivors; interpretability; patient-reported outcome measurement; psychometric properties; quality of working life; responsiveness.