Heart Failure, Sex, and Mortality Risk After Noncardiac Surgery
Does the magnitude of association between heart failure (HF) and increased risk of postoperative mortality differ in male versus female patients?
Background: Previous studies have shown higher postoperative mortality after noncardiac surgery (NCS) in HF patients. Other studies suggest lower rates of postoperative mortality after NCS in female patients. This study asks whether the magnitude of association between HF and increased risk of postoperative mortality differs in male versus female patients.
Patients from the US Department of Veterans Affairs Surgical Quality Improvement Project database, having elective NCS between October 1, 2009 and September 30, 2016, were evaluated to determine incidence of 90-day postoperative mortality. HF was established by ≥1 admission or ≥2 outpatient HF diagnostic codes, or excluded in absence of HF code documentation within 3 previous years. HF was subcategorized by left ventricular ejection fraction (LVEF), and covariates reflecting management and comorbidity were entered into two mixed effects logistical models. The first model compared 90-day postoperative mortality in men versus women with HF. The second model evaluated males and females separately, comparing 90-day mortality with and without HF in each sex stratum.
A total of 609,735 patients were included in the analysis. Of that entire population, most patients (91.4%) were male, and overall 7.9% of patients had HF. A slight majority with HF had LVEF ≥40%. Males more often had reduced LVEF, received beta-blocker and angiotensin-converting enzyme inhibitor/angiotensin-receptor blocker treatments, and had other vascular and medical comorbidities. Among patients with HF, unadjusted 90-day mortality rates were higher in males compared to females (5.55% vs. 3.59%, odds ratio [OR], 0.63; 95% confidence interval [CI], 0.48-0.85). However, after risk adjustment, odds of 90-day mortality did not differ significantly by sex (adjusted OR, 0.97; 95% CI, 0.71-1.32). In the overall population, patients with HF had fourfold higher rate of 90-day mortality (5.50% vs. 1.24%). After stratification by sex, HF showed a relatively greater association with 90-day mortality among females compared to males, in both crude (OR, 10.7 vs. 4.4) and adjusted models (adjusted OR, 2.4 vs. 1.6).
Among a large retrospective cohort of US military veterans undergoing elective NCS, both males and females with HF had significantly increased risk of 90-day postoperative mortality. In contrast to findings in the general study population, female sex in the HF subpopulation showed no protective advantage against 90-day postoperative mortality.
In one sense, extrapolation of findings on comparative postoperative mortality risk in female patients with HF may be challenging due to imbalance of other risk factors between sexes, and the relatively small representation of female patients. Regardless, these findings underscore the clinical importance of HF as a risk factor for patients undergoing NCS in both sexes.
Keywords: Adrenergic beta-Antagonists, Angiotensin Receptor Antagonists, Angiotensin-Converting Enzyme Inhibitors, Comorbidity, Heart Failure, Outpatients, Quality Improvement, Risk Adjustment, Secondary Prevention, Stroke Volume, Surgical Procedures, Elective, Vascular Diseases, Veterans, Women
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