A new retrospective cohort study shows that female Medicare beneficiaries who undergo coronary artery bypass grafting (CABG) are more likely than men to receive care at low-quality hospitals. Catherine M. Wagner, MD, MSc, and Andrew M. Ibrahim, MD, MSc, both of the University of Michigan, Ann Arbor, reported these results in a manuscript published Tuesday online in JAMA Network Open. Sex disparities at low-quality hospitals are double those at high-quality hospitals. Female patients who undergo CABG have a higher mortality rate than men, and hospital quality may have an impact on these results. Sex differences and their associations with hospital quality are not well-studied. The investigators in this study sought to examine the sex differences in 30-day mortality post-CABG in high- and low-quality hospitals. MEDPAR (Medicare Provider Analysis and Review) claims data were used to find the patients for this cross-sectional, retrospective cohort study. Data were collected for patients who underwent CABG between Oct. 1, 2015, and March 31, 2020, and data analysis took place between July 1, 2023, and Dec. 1, 2023. The primary outcome in this study was risk-adjusted 30-day mortality. A logistic regression model adjusted for sex, age, comorbidities, elective versus unplanned hospital admission, number of bypass grafts, use of arterial graft and the year of surgery. Hospital quality and sex were primary exposures, and hospitals were ranked by their overall risk-adjusted mortality rate. Hospitals were divided into quintiles. A total of 444,855 patients who were Medicare beneficiaries (mean age=71.5 years, 27.1% female; 85.9% white, 5.3% Black) were included in this study. Compared with males, female patients were more likely to have unplanned hospital admissions (48.7% versus 55.2%, p<0.001) and get care at a low-quality hospital (odds ratio [OR]=1.26, 95% confidence interval [CI]=1.23-1.29, p<0.001). Adjusting for risk, female mortality was higher than male mortality (4.24% versus 2.75%; 95% CI=2.54% to 2.62%), and there was an absolute difference of 1.01 percentage points (95% CI=0.97-1.04, p<0.001). In hospitals with the lowest quality, male mortality was 4.94% (95% CI=4.88% to 5.01%) and female mortality was 7.02% (95% CI=6.90% to 7.13%), with an absolute difference of 2.07 percentage points (95% CI=1.95-2.19, p<0.001). At low-quality hospitals, female patients had higher mortality rates than males (7.02% versus 1.57%, p<0.001). The authors noted that the 30-day mortality rate after CABG may not be an accurate measure of hospital quality. However, they also pointed out that this metric has been validated by the National Quality Foundation and that national cardiac surgery societies and national hospital rankings employ post-CABG 30-day mortality as a quality measure. Overall, female Medicare beneficiaries who received CABG had higher mortality rates than male beneficiaries, and this disparity became more pronounced as the hospital’s quality worsened. In an accompanying commentary, Jennifer Lawton, MD, of the Johns Hopkins University School of Medicine, Baltimore, discussed the past and present sex disparities in medicine, particularly cardiovascular diseases, and evaluated the results of this present study. “Even today, many clinicians lack the knowledge that more women than men died of cardiovascular disease in the US from 1984 to 2012. The American Heart Association first provided evidence-based guidelines for cardiovascular disease prevention specifically for women in 2004. Unfortunately, now 20 years later, the elevated risk of mortality after CABG in women continues to be an important clinical problem in need of attention,” the editorialist wrote. Both health and sex disparities are present in patients with cardiovascular disease, she wrote, and female patients are more likely to have uncommon symptoms. Women may also experience different comorbidities than man. The editorialist concluded by discussing the strengths and weaknesses of the present study, mentioning the limited cohort but highlighting the importance of the findings. She added that other factors besides 30-day mortality after CABG may contribute to the quality of a hospital. “A multifactorial approach that includes these strategies as well as the consideration of hospital quality, patient and clinician education, use of guideline-directed medical and surgical therapies, and increased enrollment of female patients in clinical trials is clearly needed to reduce the sex disparities in outcomes after CABG,” she concluded. Sources: Wagner CM, Ibrahim AM. Sex Disparities After Coronary Artery Bypass Grafting and Hospital Quality. JAMA Netw Open. 2024 June 11 (Article in Press). Lawton J. Improving Outcomes for Women After Coronary Artery Bypass Grafting. JAMA Netw Open. 2024 June 11 (Article in Press). Image Credit: rufous – stock.adobe.com