This study used an observational, retrospective cohort design, using US administrative insurance claims data, previously employed in an existing project, to better understand HRU and healthcare costs among women with mBC initiated on a CDK4/6 inhibitor.~Adult women with HR+/HER2- mBC initiated on a CDK4/6 inhibitor were included in the study and were stratified into cohorts based on the first CDK4/6 inhibitor they received (i.e., abemaciclib, palbociclib, or ribociclib), regardless of the line of therapy and menopausal status.~The initiation of the first CDK4/6 inhibitor was defined as the index date. The index treatment was defined as the CDK4/6 inhibitor initiated on the index date (i.e., abemaciclib, palbociclib, or ribociclib).~The 6-month period preceding the index date was considered as the baseline period, and was used to measure patient characteristics.~Outcomes were measured between the index date and 1) the end of the study period (persistence, switch, HRU, costs) OR 2) the end of the index treatment (adherence, dose modification, frequency of monitoring), as relevant. The end of the study period was defined as the earliest occurrence between the end of continuous enrollment and the end of data availability.
The study was an observational, retrospective cohort design, using US administrative insurance claims data, to better understand Healthcare resource utilization (HRU) and healthcare costs among women with mBC initiated on a CDK4/6 inhibitor.