Assessing patient, physician, and practice characteristics predicting the use of low-value services.

OBJECTIVE: To examine characteristics of beneficiaries, physicians, and their practice sites associated with greater use of low-value services (LVS) using LVS measures that reflect current care practices. DATA SOURCES: This study was conducted in the context of a large, nationwide primary care redesign initiative (Comprehensive Primary Care Plus), using Medicare claims data in 2018. STUDY DESIGN: We examined beneficiary-level total counts of LVS based on the existing 31 claims-based measures updated by excluding three services provided with diminishing frequency to Medicare beneficiaries and by replacing these with more recently identified LVS. We estimated hierarchical linear models with an extensive list of beneficiary, physician, and practice site characteristics to examine the contribution of characteristics at each level in predicting greater use of LVS. We also examined the proportion of variation in LVS use attributable to the set of characteristics at each level. DATA COLLECTION/EXTRACTION METHODS: The study included 5,074,642 Medicare fee-for-service beneficiaries attributed to 32,406 primary care physicians in 11,009 primary care practice sites. PRINCIPAL FINDINGS: Patients with disabilities, end-stage renal disease, and those in regions with higher poverty rates receive 10 (standard error [SE] = 3.0), 80 (SE = 14.0), and 10 (SE = 1.0) more LVS per 1000 beneficiaries across all 31 measures combined than patients without such attributes, respectively. Greater physician comprehensiveness and an increase in the number of primary care practitioners at a practice were associated with 40 (SE = 20.0) and 20 (SE = 6.0) fewer LVS per 1000 beneficiaries, respectively. Yet, the explanatory variables we examined only account for 11 percent of the variation in LVS use, with most of the variation (87 percent) being due to unobserved differences at the beneficiary level. CONCLUSIONS: Unexplained residual variation, from underlying patient preferences and behavior of non-primary care providers, could be important determinants of LVS use.