Population‐wide long‐term study of incidence, renal failure, and mortality rates for lupus nephritis

Abstract

ObjectiveGiven limited regional data, we investigate the state‐wide epidemiology, renal and patient outcomes for lupus nephritis (LN) in Western Australia (WA).MethodsPatients hospitalized with incident SLE (≥2 diagnostic codes in the state‐wide WA Health Hospital Morbidity Data Collection) in the period 1985–2015 were included (n = 1480). LN was defined by the presence of glomerulonephritis and/or raised serum creatinine. Trends over three study decades for annual incidence rate (AIR)/100.000 population, mortality (MR), and end‐stage renal disease (ESRD) rates/100 person years were analyzed by least square regression and compared with a matched control group (n = 12 840).ResultsClinical evidence of LN developed in 366 SLE patients (25.9%) after a median disease duration of 10 months (IQR 0–101) with renal biopsy performed in 308 (84.2%). The AIR for LN (0.63/100.000) did not change significantly over time (R2 = .11, p = .85), while point prevalence reached 11.9/100.000 in 2015. ESRD developed in 14.1% (n = 54) of LN patients vs. 0.2% in non‐LN SLE patients and 0.05% in controls (all p ≤ 0.01). ESRD rates increased over time in LN patients (0.4 to 0.7, R2 = .52, p = .26). The odds ratio for death was 8.81 (CI 3.78–22.9) for LN and 6.62 (CI 2.76–17.9) for non‐LN SLE patients compared to controls and MR for LN patients increased over time (1.3 to 2.2, R2 = .84, p = .26).ConclusionsThe incidence rate of LN in WA remained unchanged over 30 years. A lack of improvement in renal failure and mortality rates illustrates the pressing need for better long‐term treatment options and/or strategies in LN.