The Effects of Market Competition on Cardiologists' Adoption of Transcatheter Aortic Valve Replacement.

Abstract

For decades, the prevailing assumption regarding the diffusion of high-cost medical technologies has been that competitive markets favor more aggressive adoption of new treatments by health care providers (ie, the "Medical Arms Race"). However, novel regulations governing the adoption of transcatheter aortic valve replacement (TAVR) may have disrupted this paradigm when TAVR was introduced. The objective of this study was to assess the relationship between the market concentration of physician group practices and the adoption of TAVR in its first years of use. This was a retrospective cohort study. Physician group practices (n=5116) providing interventional cardiology services in the United States from May 1, 2012, to December 31, 2014. The first use of TAVR as indicated by a fee-for-service Medicare claim. Covariates including characteristics of the physician groups (ie, case volume, hospital affiliation, mean patient risk) as well as county-level and market-level characteristics. By the close of 2014, 9.3% of practices had adopted TAVR. Cox proportional hazards models revealed a hazard ratio of 1.26 (95% confidence interval: 1.16-1.37, P<0.001) per 1000 point increase in the physician group practice Herfindahl-Hirschman Index, indicating each 1000 point increase in group practice Herfindahl-Hirschman Index was associated with a 26% relative increase in the rate of TAVR adoption. Adoption of TAVR by physician groups in concentrated markets was potentially a consequence of the unique regulations governing TAVR reimbursement, which favored the adoption of TAVR by physician groups with greater market power. These findings have important implications for how future regulations may shape patterns of technology adoption.