Although the incidence of end-stage renal disease (ESRD) and mortality is extremely high among Medicaid beneficiaries with incident lupus nephritis, no statistically significant differences in these outcomes have been observed among men vs women, according to the results of a large, nationwide study published in Arthritis & Rheumatology.
The investigators sought to examine sex differences in healthcare utilization, ESRD, and mortality among patients with lupus nephritis who were receiving Medicaid. Researchers used billing claims data from the Medicaid Analytic eXtract (MAX) to identify individuals between 5 and 65 years with incident lupus nephritis. Data from MAX were linked with the US Renal Data System to determine ESRD and to the Social Security Death Index to determine mortality. Poisson regression was used to estimate adjusted incidence rate ratios (IRRs) for healthcare utilization.
A total of 2750 participants with incident lupus nephritis were enrolled in the study, including 283 men and 2467 women. The mean follow-up period was 3.1±2.3 years. The mean patient age was 29.6±13.9 years in women and 24.7±14.1 years in men (P <.01). Fewer outpatient visits (IRR, 0.88; 95% CI, 0.80-0.97) and fewer emergency department visits (IRR, 0.75; 95% CI, 0.63-0.90) were reported among men compared with women.
The 5-year cumulative incidence of ESRD was 22.3% among men vs 21.2% among women. Additionally, the 5-year cumulative incidence of mortality was 9.4% in men vs 9.8% in women. When male participants were compared with female participants, no sex differences in ESRD (hazard ratio[HR], 1.05; 95% CI, 0.76 to 1.45) or mortality (HR, 0.81; 95% CI, 0.47 to 1.35) were reported.
The investigators concluded that in this particularly vulnerable population of patients with incident lupus nephritis, biologic and healthcare utilization differences by gender may not significantly affect patient outcomes. These findings provide further evidence that heightened efforts are warranted to improve care among these patients.
Feldman CH, Broder A, Guan H, Yazdany J, Costenbader KH. Sex differences in health care utilization, end-stage renal disease, and mortality among Medicaid beneficiaries with incident lupus nephritis. Arthritis Rheumatol. 2018;70:417-426.