Sex Differences in Re-admissions following Cardiovascular Events in Patients with Kidney Failure

Background: Hospitalization for cardiovascular disease (CVD) is common in patients with kidney failure. Little is known about sex differences in readmissions following cardiovascular events in patients on dialysis. Methods: We evaluated 73,210 patients who initiated maintenance dialysis between 7/1/2013 and 6/30/2018 using the United States Renal Data System with linked Medicare claims for all cardiovascular (CV) hospitalizations. Rates of all-cause and CV related readmissions in the ensuing 30 days and 90 days were calculated. Adjusted time-to-event models were used to examine the association of sex with the outcome of 30 day and 90 day all-cause readmissions, CV readmissions, and all-cause death. Results: Among 140,171 identified CV hospitalizations, the mean age at the time of index CV hospitalization was 70±11 years, and 46.1% of index CV hospitalizations were for women. 34.9% and 57.6% of CV hospitalizations resulted in readmission within 30 and 90 days, respectively; less than one-third of readmissions were CV related (16.1%, 30 days; 29.7%, 90 days). Women had a 6% higher risk of 30 day readmission for any hospitalization (HR, 1.06; 95% CI, 1.11-1.14) and a 14% higher risk of 90-day readmission for any hospitalization (HR, 1.14; 95% CI, 1.11-1.16) after an index CV hospitalization than men. While there was no difference in the risk of 30 readmission for CV hospitalization between men and women, women had a slightly higher risk of 4% for 90 readmission for CV hospitalization (HR, 1.04; 95% CI, 1.01-1.06) after an index CV hospitalization. After an index CV hospitalization, women had a lower risk of 30 day all-cause death (HR, 0.87; 95% CI, 0.84-0.91) and a lower risk of 90 day all-cause death, as compared to men (OR, 0.89; 95% CI, 0.86-0.92). Conclusion: Among patients undergoing dialysis, women have a higher risk of readmission at 30 days and 90 days for any hospitalization and a higher risk of 90 day readmission for CV hospitalization following an index CV hospitalization than men. Further studies are needed to understand better the factors associated with sex differences in CV outcomes in patients with kidney failure. Funding: Other NIH Support - 1K23HL151816-01A1 from NHLBI