Prostate cancer outcomes among older men: insurance status comparisons results from CaPSURE database

With growing number of older adults in the United States and complexity of issues related to Medicare and other insurances more research is needed to evaluate an effectiveness of the different insurance types in prevention, screening and treatment of cancer. With prostate cancer being highly prevalent disease in older men, the importance of appropriate treatment and favorable outcomes is imperative. In this study we examine whether prostate cancer outcomes, such as risk category at diagnosis, treatment and survival differ in relationship to insurance status in older patients in CaPSURE. Data were abstracted from CaPSURE, a longitudinal observational database of 13 124 men with prostate cancer. Men were selected for the study if they were older than 65 years old at diagnosis, newly diagnosed between 1995 and 2005 at entry to CaPSURE with localized disease and received radical prostatectomy (RP), external beam radiation (EBRT), brachytherapy (BT), hormonal therapy or expectant management (EM). Insurance status was summarized by eight categories: Medicare only, Medicare+supplement, Medicare+HMO, Medicare+PPO, Medicare+FFS, health maintenance organization (HMO), preferred provider organization (PPO) and Veteran's Administration (VA). A total of 2983 men met the inclusion criteria. Odds ratios (OR) for the likelihood of receiving each type of therapy compared to RP by insurance status and likelihood of presenting with high-risk classification at diagnosis were derived using multinomial logistic regression, adjusting for clinical and demographic characteristics. Difference in survival between insurance groups was evaluated by Cox's multivariate regression. Multivariate analysis demonstrated a strong association between initial treatment and insurance status. Compared to Medicare patients, men in the CaPSURE database treated at HMO, PPO and VA systems were more likely to receive BT than RP (OR, 1.71-1.92) and less likely to receive this treatment if they were in Medicare+FFS and Medicare+PPO (OR, 0.18-0.38). Hormonal treatment demonstrated similar pattern, however OR did not reached statistical significance for HMO and PPO. Use of EM was much more predominant for patients in VA system (OR, 4.74; 95% CI, 1.94-11.55). Use of EBRT was significantly associated with type of insurance. Men with VA, Medicare+FFS and Medicare+PPO insurance were less likely to receive this treatment compared to RP. Survival and clinical risk at diagnosis was associated with insurance status in univariate analysis but this association diminished after adjusting for possible covariates. This study provides important information on relationship between insurance status and several outcomes in patients with prostate cancer. Even after controlling for important clinical and sociodemographic factors we found marked differences in prostate cancer treatment according to type of insurance. Future explorations of associations between health care delivery system, cancer care and outcomes are needed.