Sex Differences in Hospitalizations with Maintenance Hemodialysis

Hospitalization is a major source of morbidity among patients with ESRD undergoing maintenance hemodialysis and is a significant contributor to health care costs. To identify subgroups at the highest risk of hospitalization, we analyzed by sex, age, and race, adjusting for demographic and clinical characteristics, the hospitalization rates, and 30-day readmissions for 333,756 hospitalizations among 111,653 patients undergoing maintenance hemodialysis in facilities operated by a large dialysis organization in the United States (2007-2011). The overall hospitalization rate was 1.85 hospitalizations per person-year and was much higher among women than amongmen (2.08 versus 1.68 hospitalizations per year for women versus men, P<0.001). Age group-specific hospitalization rates were consistently higher forwomen than for men of the same race, and the differences were greatest in younger age groups (for example, women aged 1834 years and $75 years had 54%[95% confidence interval, 42% to 67%] and 14%[95% confidence interval, 11% to 18%] higher hospitalization rates, respectively, than did men of respective ages). Women also had substantially higher risk for 30-day readmission, with the largest differences at younger ages. Women had a significantly lower serum albumin level than men, and stratification by serum albumin level attenuated sex differences in the age group-specific hospitalization and 30-day readmission rates. These findings suggest that women undergoingmaintenance hemodialysis have substantially higher risks for hospitalization and 30-day readmission than men. In this cohort, the sex differences were greatest in the younger age groups and were attenuated by accounting for differences in health status reflected by serum albumin level.