Factors Associated with Renal Outcomes in an Inception Cohort of Biopsy-proven Lupus Nephritis Patients

Abstract

Objective: To identify the clinical factors associated with renal response and flare in lupus nephritis (LN). Methods: All 115 patients with biopsy-proven LN diagnosed between January 2002 and June 2015 in a tertiary centre comprised of an inception cohort that was followed up until February 2017. Baseline demographic, clinical parameters, renal biopsy histology, induction and maintenance immunosuppressive therapies, complete renal response (CRR), creatinine doubling, end-stage renal disease (ESRD), renal flares and infections were retrieved and analyzed with univariate log-rank test and multivariate Cox regression. Results: At the time of the first renal biopsy, the age of patients was 38 ± 12.2 years (mean ± standard deviation), 90% female and systemic lupus erythematosus (SLE) disease duration 46 months (median); 67.0% were LN class IV or class IV + V. Patients were followed up for 104 ±49 months after biopsy. At months 3, 6, 12 and 24, a cumulative 25%, 46%, 66% and 76% of patients had achieved CRR, respectively. However, 49.5% who had CRR experienced ≥1 infection of renal flare, with cumulative risk of 5%, 17%, 25% and 43% at year 1, 2, 3 and 5, respectively. Multivariate analysis showed that nephrotic syndrome (p = 0.03) and delay of renal biopsy ≥2 months from the onset of LN (p ¡ 0.01) were negatively associated with CRR. Hydroxychloroquine use was beneficial in attaining CRR (p = 0.03, hazard ratio = 1.70, 95% CI: 1.04, 2.80) and preventing renal flare (p = 0.01, odds ratio = 0.51, 95% CI: 0.29, 0.88). By the end of the study, 80% of patients remained in CRR though 10.4% patients ended up in ESRD (all class IV), 8.7% died and 28.7% had ≥1 infection episode requiring hospitalization. Conclusion: Most LN patients could achieve CRR after immunosuppressive therapy but renal flares were common over time. Infective complications were fairly frequent but the incidence of ESRD was low. The use of hydroxychloroquine was associated with better renal response and fewer flares.

Keywords

• systemic lupus erythematosus
• lupus nephritis
• treatment
• cohort