Long-term mortality and renal outcome in a cohort of 100 patients with lupus nephritis

Abstract

Objective: To evaluate the long-term mortality and renal outcome in a cohort of Danish patients with lupus nephritis (LN) and to identify outcome predictors among findings registered at the time of the first renal biopsy.

Methods: The cohort consisted of 100 patients diagnosed with LN (World Health Organization classes I-VI) between 1971 and 1995 and followed for a median duration of 14.7 years (range 0.01-36.9 years). Standardized mortality ratios (SMRs) were calculated on the basis of national age-, sex-, and calendar-year period-specific death rates.

Results: Thirty-seven deaths occurred in the cohort, corresponding to an overall SMR of 6.8 (95% confidence interval [95% CI] 4.9-9.4). Excess mortality was observed throughout followup. The SMR estimates were 9.0 (95% CI 4.7-17.1), 6.2 (95% CI 4.0-9.5), and 6.6 (95% CI 3.1-13.8) for patients diagnosed during the calendar-year periods 1971-1979, 1980-1989, and 1990-1995, respectively. The cumulative renal survival after 5, 10, and 20 years of followup was 87%, 83%, and 73%, respectively. The risk of end-stage renal disease (ESRD) did not decrease significantly across calendar-year periods. Systolic blood pressure >or=180 mm Hg, focal segmental nephritis, and advanced sclerosing nephritis were identified as baseline predictors of death in multivariate regression analyses, while systolic blood pressure >or=180 mm Hg, serum creatinine level >or=140 mumoles/liter, and diagnostic delay predicted progression to ESRD.

Conclusion: LN is associated with excess long-term mortality, and patients may progress to ESRD even after prolonged followup. Our analyses indicate that focal segmental histopathology at disease onset constitutes an important risk factor for death among LN patients. Moreover, our data underscore the importance of early intervention, blood pressure control, and long-term followup in LN.