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.