Background: Certificate of need (CON) regulation was introduced to control healthcare costs and improve quality of care in part by limiting the number of facilities providing complex medical care. Our objective was to examine whether rates of appropriate cardiac catheterization after admission for acute myocardial infarction varied between states with and without CON regulation of cardiac catheterization.
Methods and results: We performed a retrospective analysis of chart-abstracted data for 137,279 Medicare patients admitted for acute myocardial infarction between 1994 and 1996 at 4179 US acute-care hospitals. Using 3-level hierarchical generalized linear modeling adjusted for patient sociodemographic and clinical characteristics and physician and hospital characteristics, we compared catheterization rates within 60 days of admission for states (and the District of Columbia) with (n=32) and without (n=19) CON regulation in the full cohort and stratified by catheterization appropriateness. Appropriateness was categorized as strongly, equivocally, or weakly indicated. We found CON regulation was associated with a borderline-significant lower rate of catheterization overall (45.8% versus 46.5%; adjusted risk ratio [RR] 0.91, 95% confidence interval 0.82 to 1.00, P=0.06). After stratification by appropriateness, CON regulation was not associated with a significantly lower rate of catheterization among 63,823 patients with strong indications (49.9% versus 50.3%; adjusted RR 0.94, 95% confidence interval 0.86 to 1.02, P=0.17). However, CON regulation was associated with significantly lower rates of catheterization among 65,077 patients with equivocal indication (45.0% versus 46.0%; adjusted RR 0.88, 95% confidence interval 0.78 to 1.00, P=0.05) and among 8379 patients with weak indications (19.8% versus 21.8%; adjusted RR 0.84, 95% confidence interval 0.71 to 0.98, P=0.04). Associations were weakened substantially after adjustment for hospital coronary artery bypass graft surgery or cardiac catheterization capability.
Conclusions: CON regulation was associated with modestly lower rates of equivocally and weakly indicated cardiac catheterization after admission for acute myocardial infarction, but no significant differences existed in rates of strongly indicated catheterization.