Objective: We describe an integrated method for determining meaningful change in health-related quality of life (HRQOL) that combines information from anchor-based and distribution-based methods and illustrate this method using data aggregated from weight loss studies.
Study design and setting: A total of 1476 participants in weight loss studies were evaluated at baseline and at 6 months using the Impact of Weight on Quality of Life-Lite (IWQOL-Lite). Severity of baseline impairment was determined by comparing scores with those obtained from a normative sample of 534 normal/overweight individuals. The precision of the IWQOL-Lite was evaluated using standard error of measurement corrected for regression to the mean. Weight loss was used as an anchor for evaluating changes in IWQOL-Lite scores.
Results: Change in HRQOL varied as a function of weight loss and baseline severity of HRQOL. Using this integrated method, an improvement of 7.7 to 12 points (depending on baseline severity) on IWQOL-Lite total score is considered meaningful.
Conclusion: Meaningful change in HRQOL can be determined using an integrated method that (1) combines information from anchor-based and distribution-based methods, (2) reconciles discrepancies between these two methods, and (3) adjusts for baseline severity and regression to the mean. This method may be applied to other types of HRQOL measures and conditions.