Health care resource utilization and costs of Medicare-enrolled patients with HR+/HER2- metastatic breast cancer treated with a CDK4/6i in the first-line setting.

Abstract

The introduction of cyclin-dependent kinases 4 and 6 inhibitors (CDK4/6is) has transformed the treatment landscape for patients with hormone receptor positive (HR+) and human epidermal growth factor receptor 2 negative (HER2-) metastatic breast cancer (MBC). To our knowledge, no studies have quantified health care resource utilization (HRU) or economic burden following CDK4/6i initiation in the Medicare population. To describe HRU and quantify health care costs among Medicare-enrolled patients with HR+ HER2- MBC treated with CDK4/6is in the first-line setting. We conducted a retrospective cohort study on Medicare-enrolled patients with HR+ HER2- MBC who initiated a CDK4/6i in the first-line setting between February 2, 2016, and December 31, 2022, using claims from the Merative MarketScan database. We examined all-cause HRU by summarizing the number of inpatient (IP), outpatient (OP), and emergency department (ED) visits as well as the length of stay during the 6 months following CDK4/6i initiation. Additionally, we assessed all-cause health care costs, including IP, OP, ED, and pharmacy, over the 1 year following CDK4/6i initiation using the Kaplan-Meier sample average estimator to account for censoring. We reported total health care costs as the sum of IP, OP, ED, and pharmacy costs. 901 patients met the inclusion criteria with a mean age of 74 years (SD = 6.84). Nearly 24% (n = 214) had an IP admission in the 6 months following CDK4/6i initiation. Among patients with an IP admission, the mean number of admissions per patient was 1.65 (SD = 0.98) with a mean length of stay per admission of 5.98 (SD = 6.25) days. Roughly 30% (n = 271) of patients had an ED visit, with a mean of 2.1 (SD = 1.54) visits per patient among those who had a visit. Most patients (n = 868, 96.44%) had an OP service, and among those with an OP service, the mean number of days with OP services was 19.96 (SD = 12.29). Mean total health care costs over the 1-year period following CDK4/6is were $62,228 (95% CI = 52,281-73,029) per patient with the main drivers being OP services ($31,686 [95% CI = 27,168-36,925]) and pharmacy costs ($22,727 [95% CI = 19,273-25,931]). There are numerous sources of HRU and cost in patients following CDK4/6i initiation in the Medicare population. Patients with HR+ HER2- MBC incur high HRU, providing insights for health care decision-makers to optimize treatment strategies and resource allocation for this population.