Background: Medical care overuse is a significant source of patient harm and wasteful spending. Understanding the drivers of overuse is essential to the design of effective interventions.
Objective: We tested the association between structural factors of the health care delivery system and regional differences systemic overuse.
Research design: We conducted a retrospective analysis of deidentified claims for 18- to 64-year-old adults from the IBM MarketScan Commercial Claims and Encounters Database. We calculated a semiannual Johns Hopkins Overuse Index for each of the 375 Metropolitan Statistical Areas in the United States, from January 2011 to June 2015. We fit an ordinary least squares regression to model the Johns Hopkins Overuse Index as a function of regional characteristics of the health care system, adjusted for confounders and time.
Results: The supply of regional health care resources was associated with systemic overuse in commercially insured beneficiaries. Regional characteristics associated with systemic overuse included number of physicians per 1000 residents (P=0.001) and higher Medicare malpractice geographic price cost index (P<0.001). Regions with a higher density of primary care physicians (P=0.008) and a higher proportion of hospital-based providers (P=0.016) had less systemic overuse. Differences in hospital and insurer market power were inversely associated with systemic overuse.
Conclusions: Systemic overuse is associated with observable, structural characteristics of the regional health care system. These findings suggest that interventions that aim to improve care efficiency via reductions in overuse should focus on the structural drivers of this phenomenon, rather than on the eradication of individual overused procedures.