Presentation (CTI)

OBJECTIVES: Duration of health plan enrollment is an important consideration in the design of studies using payer databases. We conducted a descriptive analysis of enrollment duration among commercial and managed Medicare members of a large US health plan. We compared enrollment duration by member characteristics and five chronic diseases: type 2 diabetes mellitus (T2DM), breast cancer (BC), heart failure (HF), multiple sclerosis (MS), and Alzheimer’s disease (ALZD).
METHODS: A retrospective analysis using payer claims from the Healthcare Integrated Research Database (HIRD®). Study members had an outpatient office visit for any reason or were newly diagnosed with any of the five conditions between 10/01/2016 and 09/30/2020. Index date was date of first office visit claim or first claim with chronic disease. We required enrollment for at least a year before index date. We calculated enrollment duration from index date through 09/30/2024. Enrollment duration was calculated in months by age categories (≤17, 18-44, 45-64, ≥65 years) and race/ethnicity, and reported as median (interquartile range) months.
RESULTS: A total of 11.7 million members had an office visit during the study period. Mean age varied by condition, ranging from 48 years (MS) to 83 years (ALZD); overall mean age was 39 years. Post-index enrollment duration was 38 months (14-80) among all members, with 36% enrolled for ≥5 years. Enrollment duration was similar for members with T2DM, BC, and MS, 44 (18-68), 48 (19-69) and 40 (16-67) months, respectively. Enrollment was shorter for those with HF, 35 (11-62) and ALZD, 30 (12-54) months. Enrollment duration varied by age, ≤17 - 47 (15-85), 18-44 - 31 (12-68), 45-64 - 39 (14-81) and ≥65 - 53 (19-93), and was longest for White non-Hispanics, 41 (15-83) and shortest for Asians, 35 (13-74) months.
CONCLUSIONS: Results show that large payer databases can support studies requiring longer follow-up periods.