Validity of Pharmaceutical Claims Data for Determining Medication Exposure in Long-Term Care Facilities.

Purpose: To compare the accuracy of pharmaceutical claims with medication administration chart data for individuals in long-term care facilities (LTCFs).

Methods: Secondary analyses of a prospective cohort study (n = 279 residents, 5 LTCFs) were conducted. Details of medications charted for regular administration at study enrollment were extracted from administration charts and coded using Anatomical Therapeutic Chemical (ATC) classification codes. Pharmaceutical claims for government-subsidized medications dispensed in the 0-30, 0-60, 0-90, 0-120, and 0-180 days before study enrollment were compared to medication chart data (reference standard). Sensitivity, specificity, and positive predictive value (PPV) and 95% CIs were determined at the 3- and 7-digit ATC levels.

Results: 149 (53.4% of total) residents with both medication chart and claims data available were included. The proportion of PPVs ≥ 75% for 3-digit ATC level medications was 89.4% and 86.1% using exposure windows of 30 and 180-days for claims, respectively. Using a 120-day exposure window for claims, sensitivity was highest for diabetes agents, beta-blocking agents, calcium channel blockers, agents acting on the renin-angiotensin system, anti-Parkinson drugs, psychoanaleptics, and airways disease agents (all ≥ 90%) and was lowest for vitamins (1.4%, 95% CI 0-7.7) and mineral supplements (10.3%, 95% CI 2.9-24.2). Specificity was ≥ 85% for all 3-digit level medications within each exposure window other than antibacterials and analgesics.

Conclusion: Pharmaceutical claims data has good accuracy for determining prescription medication exposure in LTCFs. Exposure windows of 90-120-days are generally sufficient for determining exposure although longer periods may be required for large pack sizes.