Characterizing Physician Practice in Nursing Homes Using Claims-Based Measures: Correlation With Nursing Home Administrators' Perceptions.

Heterogeneity in physician practice within nursing homes (NHs) may explain variations in quality. However, data on physician practice organization in NHs are hard to obtain. We characterized NH physician practice using two claims-based measures: (a) concentration of NH care among physicians (measured by Herfindahl-Hirschman index of visits); and (b) physician NH practice specialization (measured by the proportion of a physician's visits to NHs). We examined the relationship between the measures and NH administrator perceptions of physician practice reported in the Shaping Long-Term Care in America (SLTCA) Survey. All 2011 Part B claims from 13,718 physicians who treated Medicare fee-for-service patients in 2,095 NHs in the SLTCA survey were analyzed. The median Herfindahl-Hirschman index was 0.44 (interquartile range [IQR] 0.28-0.70), and the median specialization was 38.1% (IQR 19.9% to 60.9%). NHs with higher physician specialization reported more frequent physician participation in care coordination activities. Claims-based measures could inform the study of NH physician practice.