Market and regulatory influences on the availability of coronary angioplasty and bypass surgery in U.S. hospitals.

Using 1983 data on 3720 nonfederal short-term hospitals, we analyzed the influence of local market competition and state regulatory programs on the availability of percutaneous transluminal coronary angioplasty and coronary-artery bypass surgery. The degree of competition for patients with heart disease was measured in terms of the number of hospitals in the local market area that maintained a cardiac catheterization laboratory or facility for open-heart surgery. When the patient case mix and the hospital's teaching role were controlled for, institutions with more than 20 competitors in the local area were 166 percent more likely to offer coronary angioplasty (P less than 0.0001) and 147 percent more likely to offer bypass surgery (P less than 0.0001) than hospitals with no competitors in the local market. Four fifths of the hospitals performing bypass surgery whose annual volume was less than 200 had one or more neighboring hospitals with a facility for open-heart surgery. State rate-regulation programs in New York, New Jersey, Connecticut, Massachusetts, and Maryland significantly reduced the availability of both procedures, with the greatest regulatory effects being observed in the most competitive hospital markets. We conclude that in the period under consideration, competition encouraged and regulation discouraged the proliferation of these cardiac services.