Investigating the prognostic ability of health-related quality of life on survival: a prospective cohort study of adults with lung cancer.

Abstract

Health-related quality of life (HRQOL) is an important predictor for overall survival (OS). To date, no studies compared associations between HRQOL assessed before and after a cancer diagnosis for OS. Our objectives were to (1) investigate associations between HRQOL changes and OS and (2) identify the best HRQOL assessment time point to predict OS. We used the Surveillance, Epidemiology and End Results linked with the Medicare Health Outcomes Survey data. Medicare Advantage beneficiaries with SEER-confirmed, incident lung cancer between 1998 and 2013 were included. We only included individuals who completed pre- and post-diagnosis assessments. HRQOL was captured using the Short-Form (SF-36) and Katz's Activities of Daily Living (ADL). Cox Proportional Hazards models examined associations between HRQOL and OS, adjusting for potential confounders. AICs compared model fit. Five hundred thirty-five adults with mean age of 75years at diagnosis were included. We observed 300 deaths. Poor HRQOL was associated with greater risk of death across HRQOL assessments. SF-36 before diagnosis, after diagnosis, and change over time had AHRs of 1.01-1.08, 1.10-1.20, and 1.06-1.12, respectively. Pre-diagnosis, post-diagnosis, and changes in ADLs had AHRs of 0.90-2.06, 1.72-2.56, and 1.66-2.21, respectively. Post-diagnosis HRQOL and HRQOL change models had the smallest AICs and largest AHRs, suggesting they were most associated with OS. This is the first study to compare the prognostic ability of pre-diagnosis, post-diagnosis, and HRQOL changes for OS. The prognostic value of HRQOL at distinct points in the cancer continuum underscores the importance of routine HRQOL monitoring as part of patient-centered cancer care.