Specialty Cardiac Hospitals and Coronary Revascularization RatesSpecialty Cardiac Hospitals and Coronary Revascularization Rates

To the Editor: In their article on the effect of physician-owned cardiac hospitals on rates of cardiac surgery, Dr Nallamothu and colleagues¹ stated their results “differ somewhat” from the results reported in the Medicare Payment Advisory Commission (MedPAC) 2005 congressionally mandated study on specialty hospitals.^{2 - 3} The MedPAC 2005 study looked at data through 2002, while Nallamothu et al analyzed data through 2003. In 2006, MedPAC issued a refined version of its analysis that examined changes in volume through 2004.⁴

We want to clarify that the results of the MedPAC 2005 and 2006 studies and Nallamothu et al are all consistent (Table). Nallamothu et al took into account whether and how long a specialty hospital operated in a market. The authors note that the initial 2005 MedPAC study made a simple dichotomous comparison between markets with and without a physician-owned heart hospital. However, in the 2006 study, MedPAC did consider how long a facility had been open and took into account each physician-owned hospital's market share.

Despite the methodological differences between the MedPAC and Nallamothu et al studies, the results are largely in agreement. The studies had the same finding on coronary artery bypass graft volume. The “differing somewhat” refers to the level of significance of the regression coefficients on the variable measuring change in percutaneous coronary intervention volume, not in the sign of the regression coefficients. Both studies found that opening physician-owned cardiac hospitals was associated with higher rates of some cardiac surgeries. The MedPAC studies differ from Nallamouthu et al in emphasizing that while physician-owned hospitals are associated with some increases in volume, most of the cardiac hospital patients came from capturing market share from full-service community hospitals, not the increase in volume.