Angina and Cardiac Care: Are There Gender Differences, and If So, Why?
D ifferences in cardiac care according to gender have now been described for 20 years. As early as 1987, Tobin et al 1 reported that 40% of male patients with abnormal exercise radionuclide scans were referred for cardiac catheterization, whereas only 4% of the female patients were referred for future testing. Since then, many investigations have continued to describe a less aggressive management strategy for coronary artery disease (CAD) in women than in men in a variety of settings, but
... inantly in patients with acute coronary syndromes. 2-11 Article p 490 Women are normally protected against CAD as compared with men until elderly age, but once they experience an acute myocardial infarction (MI), they have poorer outcomes than their male counterparts, particularly if they are younger than 60 years. 12,13 It is possible that underrecognition and undertreatment of CAD in its early phase in women is a contributory factor. This may lead to 2 possible scenarios: (1) a more advanced or complicated disease at the time of MI due to lack of preventive treatment, and (2) referral bias due to the fact that only the most severely affected or the most symptomatic women with CAD are eventually diagnosed and treated. Angina pectoris is the most common initial presentation of symptomatic CAD in women and therefore represents, in many cases, the starting point in the sequence of healthcare delivery events that may result in gender-related inequalities. If there is lower utilization of noninvasive diagnostic testing at this initial point of care, it may translate into delayed diagnosis, delayed initiation of therapeutic interventions, and ultimately worse outcomes. Recognition of such underutilization, therefore, would shed light on whether the more advanced level of symptom severity, comorbidity, and often worse outcomes of women at the time of an MI are due to earlier undertreatment or referral bias. Surprisingly, data are limited about referral patterns according to gender early in the course of CAD, perhaps because of the complexities of collecting a sufficiently large sample of these data in a systematic fashion. The report by Daly et al 14 in this issue of Circulation represents a useful step toward filling this gap. This multinational investigation is the largest evaluation of management and outcome of chronic stable angina according to gender in recent years. It reports on 2197 male and 1582 female patients who received a new diagnosis of stable angina by a cardiologist in 197 participating cardiology services in Europe. Clinical information on the patients and management strategies performed or planned were recorded, and patient follow-up was obtained at 1 year. The results of this study indicate a systematically lower utilization of treatments and diagnostic procedures in women than in men, even though both groups had received a diagnosis of angina pectoris from a cardiologist, and women had a higher angina class. At the initial assessment, women were less likely to be prescribed antiplatelet and statin therapy (despite similar rates of hyperlipidemia) and to be referred for further evaluation with exercise ECG (73% of women and 78% of men) and coronary angiography (31% of women and 49% of men). Adjustment for comorbidity, symptom characteristics, and other factors did not account for the gender differences in procedures, and observed management differences persisted almost unaltered at 1 year. One obvious explanation for the lower referral of women for coronary angiography is the lower rate of positive stress tests in this group; however, among patients with a positive ECG stress test, a significantly lower proportion of women (56%) than men (65%) received coronary angiography at 1 year. Additionally, among patients with demonstrated CAD by angiography, women had 30% lower adjusted odds of receiving revascularization than men. Even differences in severity of CAD at angiography did not explain gender-based variations in revascularization when added to the model. The latter results are in contrast to other investigations showing that once coronary anatomy is defined by coronary angiography, gender is not an independent predictor of revascularization procedures. 3, 15, 16 A strength of the present study was the examination of patients' outcomes, because this may shed some light on the clinical implications of withholding appropriate patient care. In the entire population, there were no differences in angina symptoms and major cardiovascular events (death or MI) between men and women; however, among patients with confirmed CAD at angiography, women experienced worse outcomes. They continued to experience more angina and had approximately twice the rates of death or MI at 1 year as compared with men. There are 2 possible explanations of these results. First, differential referral by gender was appropriately due to the lower risk of women, 17 but because women with confirmed CAD received fewer secondary prevention