A measure of quality of life after abdominal surgery

Introduction: A major limitation of clinical trials evaluating laparoscopic surgical procedures has been the lack of a valid and reliable measure of short-term quality of life after abdominal surgery.Methods: We used existing health status measures, focus groups, and semi-structured patient interviews to generate a prototype questionnaire of 51 items, which was administered to patients within 2 weeks after an abdominal surgical procedure. We used principal components factor analysis with varimax rotation to identify the health status domains underlying the concept of post-operative quality of life, and to reduce the number of items. We then used structural equation modeling to perform a confirmatory factor analysis to assess the reliability and construct validity of the instrument.Results: We administered the prototype questionnaire to 500 patients (mean age [SD] 53.4 [16.0], 51.4% male, 73.0% inpatient) at a mean 4.1 days after an abdominal surgical procedure. We retained the 3 items with the highest factor loadings on each of the 6 factors that accounted for variation in quality of life after abdominal surgery (Table). This produced an 18-item measure with 6 sub-scales. The overall scale reliability was excellent (Cronbach’s alpha 0.91). The confirmatory factor analysis on the final instrument demonstrated good reliability and validity in relation to our hypothesized factors (root mean square error of approximation 0.085, goodness-of-fit index 0.89). TableFactors extracted in the principal components analysisPhysical limitationsFunctional impairmentPainVisceral functionSleepPsychological functionConclusions: We developed a reliable and valid 18-item, 6-subscale measure of health-related quality of life after abdominal surgery, for use as an outcome measure in studies comparing laparoscopic and conventional abdominal surgery.