Ayanian JZ, Epstein AM.
Differences in the use of procedures between women and men hospitalized for coronary heart disease.
NEJM 1991;325(4):221-5. (Comments in: NEJM 1991;325(4):274-6. NEJM 1992;326(8)570-1; NEJM 1992;326(8):570; discussion 571.)

The purpose of this study was to assess whether there were sex-related differences in two states (Massachusetts and Maryland) in the use of coronary procedures among all patients hospitalized for coronary heart disease in 1987. In Massachusetts and Maryland, the study population represented 73.3% and 77.3% respectively of all patients undergoing inpatient coronary angiography and 84.5% and 94.7% respectively of all patients undergoing revascularization – coronary-artery bypass surgery (CABG) or percutaneous transluminal coronary angioplasty (PCTA).

The overall rates of coronary angiography in the Massachusetts and Maryland cohorts were 27.5% and 28.7% for men and 16.1% and 17.7% for women respectively. For coronary revascularization, the respective rates were 15.5% and 14.1% for men and 7.4% and 6.5% for women. Men were still more likely to undergo angiography and revascularization after adjustment for potential clinical and demographic confounders.

The authors note several potential reasons for the observed gender differences. First, men may undergo more procedures than women if physicians view coronary heart disease (CHD) as more severe among men because of higher incidence of disease. Second, the rates at which procedures are performed may be influenced by physicians' perceptions of sex-related differences in risk and efficacy. Third, the rate of hospital admission for women with ischemic symptoms in the absence of true CHD may be higher. Finally, patient preferences and sex bias in the delivery of medical care might be operating. The authors conclude that "further study will be necessary to determine whether the differences in rates of procedures reflect appropriate clinical practice or whether the outcomes in women with CHD are compromised by these differences."

Although the aim of the study was not to assess race differences, it is notable that such differences were found. With regard to coronary angiography in Massachusetts, the rates for white men and women were 28.1% and 16.4%, while the rates for black men and women were 19.7% and 12.9% respectively. In Maryland, the rates for white men and women were 29.9% and 18.5%, while the rates for black men and women were 21.8% and 14.8%. Similarly, with regard to coronary revascularization in Massachusetts, the rates for white men and women were 18.8% and 9.4%, while the rates for black men and women were 14.0% and 8.6%. In Maryland, the rates for white men and women were 17.7% and 8.9%, while the rates for black men and women were 10.3% and 4.8%. The authors do not discuss these findings.