Objective: We sought to evaluate differences in the stage at diagnosis and the survival of breast cancer patients enrolled in two different Medicare healthcare delivery systems: fee for service (FFS) and health maintenance organizations (HMO).
Methods: We used a linkage of two national databases, the Medicare database from the Centers for Medicare and Medicaid Services (CMS), and the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) program database, to evaluate differences in demographic data, stage at diagnosis, and survival in patients with breast cancers over the period 1985-2001.
Results: Medicare patients enrolled in HMOs were diagnosed at an earlier stage of diagnosis than FFS patients. HMO patients diagnosed with breast cancer had improved survival, and these differences remained even after controlling for potential confounders. Specifically, breast cancer patients enrolled in HMOs had 9% increased probability of survival (hazard ratio [HR] 0.91, 95% confidence interval [CI] 0.88-0.93) than their counterparts enrolled in FFS. These findings persisted even when patients had a cancer diagnosis before their breast cancer.
Conclusions: Improved survival among breast cancer patients in HMOs compared with FFS is likely due to a combination of factors, including but not limited to earlier stage at the time of diagnosis.