From Bad to Worse
Comorbidity Severity and Quality of Life After Treatment for Early-Stage Prostate Cancer
Published in: Prostate Cancer and Prostatic Diseases, v. 13, no. 4, Dec. 2010, p. 320-327
Posted on RAND.org on December 31, 2009
Commonly used measures of comorbidity assess comorbidity number and type but not severity. We sought to evaluate the impact of comorbidity severity on longitudinal health-related quality of life (HRQOL) in men treated with radical prostatectomy (RP) or radiation therapy (RT) using the Total Illness Burden Index for prostate cancer (TIBI-CaP). We sampled 738 men with non-metastatic prostate cancer treated with RP or RT from the Cancer of the Prostate Strategic Urologic Research Endeavor registry. We examined the impact of comorbidity severity on generic and disease-specific HRQOL at baseline and at 6, 12, 18 and 24 months post-treatment. Men with worse TIBI-CaP comorbidity had significantly lower baseline and post-treatment HRQOL in all domains at all time points. In a multivariate model, men with moderate or severe TIBI-CaP comorbidity had significantly worse HRQOL scores at 12 and 24 months after treatment in all domains except sexual and urinary function (P<0.05); in these domains, severe comorbidity was predictive of lower HRQOL (P<0.05). Comorbidity groups had similar absolute declines in HRQOL from baseline to 6 and 24 months after treatment. Although comorbidity groups experienced similar long-term declines from baseline HRQOL after treatment, men with more severe comorbidity had significantly lower baseline scores and therefore poorer long-term HRQOL.