Incidence- Versus Prevalence-Based Measures of Inappropriate Prescribing in the Veterans Health Administration

Abstract

Objectives To describe variations in potentially inappropriate prescribing (PIP) and characterize the extent to which switching to an incidence-based indicator would affect health system quality rankings. Design Observational study. Setting Veterans Health Administration in 2011. Participants Older adults receiving outpatient primary care. Measurements PIP was defined according to the National Committee for Quality Assurance High-Risk Medications in the Elderly list. Ranks were separately assigned for prevalent and incident PIP at the regional, network, and healthcare system levels. Results National PIP prevalence was 12.3% (167,766/1,360,251), and incidence was 5.8% (78,604/1,360,251). PIP prevalence ranged from 3.5% to 33.1% across healthcare systems (interquartile range (IQR) = 9.2-15.5%). PIP incidence ranged from 1.2% to 14.9% (IQR = 4.1-7.2%). Rank order in PIP prevalence and incidence was correlated (Spearman correlation; ρ = 0.934, P