Cost-Efficiency of Breast Cancer Care in the US Military Health System: An Economic Evaluation in Direct and Purchased Care

Abstract

With the rising costs of cancer care, it is critical to evaluate the overall cost-efficiency of care in real-world settings. In the United States, breast cancer accounts for the largest portion of cancer care spending due to high incidence and prevalence. The purpose of this study is to assess the relationship between breast cancer costs in the first 6 months after diagnosis and clinical outcomes by care source (direct or purchased) in the universal-access US Military Health System (MHS). Materials and Methods: We conducted a retrospective analysis of data from the Department of Defense Central Cancer Registry and MHS Data Repository administrative records. The institutional review boards of the Walter Reed National Military Medical Center and the Defense Health Agency reviewed and approved the data linkage. We used the linked data to identify women aged 40-64 who were diagnosed with pathologically-confirmed breast cancer between 2003 and 2007 with at least 1 year of follow-up through December 31, 2008. We identified cancer treatment from administrative data using relevant medical procedure and billing codes and extracted costs paid by the MHS for each claim. Multivariable Cox proportional hazards models estimated hazards ratios (HR) and 95% confidence intervals (CI) for recurrence or all-cause death as a function of breast cancer cost in tertiles. Results: The median cost per patient (n = 2,490) for cancer care was $16,741 (interquartile range $9,268, $28,742) in the first 6 months after diagnosis. In direct care, women in the highest cost tertile had a lower risk for clinical outcomes compared to women in the lowest cost tertile (HR 0.58, 95% CI 0.35, 0.96). When outcomes were evaluated separately, there was a statistically significant inverse association between higher cost and risk of death (p-trend = 0.025) for women receiving direct care. These associations were not observed among women using purchased care or both care sources. Conclusions: In the MHS, higher breast cancer costs in the first 6 months after diagnosis were associated with lower risk for clinical outcomes in direct care, but not in purchased care. Organizational, institutional, and provider-level factors may contribute to the observed differences by care source. Replication of our findings in breast and other tumor sites may have implications for informing cancer care financing and value-based reimbursement policy.