Sex differences in long-term outcomes of patients across the spectrum of coronary artery disease

Abstract

Background: Patients with nonobstructive coronary artery disease (CAD) have worse outcomes compared with those without CAD; however, few studies have compared the intermediate- and long-term impact of CAD severity as a function of patient sex.

Methods: We evaluated 5-year and long-term all-cause mortality of women and men undergoing elective coronary angiography at a single center by degree of CAD: no CAD (1%-24% stenosis), nonobstructive CAD (25%-69% epicardial stenosis or 25%-49% left main stenosis), or obstructive CAD (epicardial stenosis ≥70% or left main stenosis ≥50%), both overall and after adjusting for baseline clinical risk factors using Cox proportional-hazards models.

Results: Between January 1986 and July 2010, 8,766 women and 11,638 men underwent angiography and were followed for a median of 9.2 years. The majority (67%) of women had no CAD or nonobstructive CAD, whereas the majority of men had obstructive CAD (56%, P < .001). In both sexes, increasing CAD was associated with increased 5-year risk of mortality. Risk-adjusted hazard ratios (vs no CAD) for women were 1.36 (95% CI, 1.16-1.60) and 1.86 (1.61-2.16) for nonobstructive and obstructive CAD, respectively; corresponding hazard ratios for men were 1.24 (1.06-1.45) and 1.38 (1.20-1.59). After risk adjustment, 5-year mortality risk was higher in men than in women at all levels of CAD severity. The relationships between severity of CAD and mortality risk during long-term follow-up in women and men were similar to the 5-year relationships above.

Conclusions: Although women undergoing elective catheterization have less severe CAD than men, nonobstructive CAD is prevalent in both sexes and carries a worse prognosis than no CAD. These data suggest a need for further investigation to establish optimal therapies for this at-risk group of patients with nonobstructive CAD.

Figure 1

Flowchart of patient selection. ACS, acute coronary syndrome; AMI, acute myocardial infarction; CABG, coronary artery bypass grafting; cath, catheterization; IHD, ischemic heart disease; PCI, percutaneous coronary intervention.

Figure 2

CAD severity distribution by sex.

Figure 3

Five-year cumulative incidence of mortality by CAD severity level within each sex.

Figure 4

Five-year cumulative incidence of mortality by number of diseased vessels within each sex. V, vessel; Non-obs, nonobstructive; Obs, obstructive.

Figure 5

Adjusted comparison of 5-year mortality between men and women at each level of CAD severity. A, Comparison of men and women at each level of CAD severity. B, Comparison of men and women at each level of CAD severity to women with no CAD.