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

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.