Responsive and monophasic lupus nephritis: prevalence, associations and outcomes.

Abstract

LN is associated with significant renal morbidity, although some patients may experience a responsive and monophasic course. We aimed to assess the proportion of LN patients with such a course and identify its associated baseline characteristics. This retrospective study included SLE patients from an observational cohort who developed LN at or after clinic entry. A responsive and monophasic course was defined as complete proteinuria recovery within 1 year for subnephrotic- or 2 years for nephrotic-range proteinuria, without subsequent renal flares. Univariable and multivariable logistic regression were used to assess the impact of baseline characteristics on developing a responsive and monophasic course, while Cox regression was used to explore the association with a long-term adverse composite outcome, including end-stage kidney disease, sustained ≥30% estimated glomerular filtration rate (eGFR) decline, or death. Among 374 LN patients (mean age: 32.8 years; 89.2% female; median follow-up: 10.6 years), 96 patients (25.7%) exhibited a responsive and monophasic course, which was associated with older age [odds ratio (OR) 1.04, 95% CI 1.01-1.07] and shorter SLE duration (OR 0.91, 95% CI 0.86-0.97) at LN onset. In the Cox model, timely recovery of proteinuria and the absence of subsequent LN flares were associated with a reduced risk of the adverse composite outcome. Despite these associations, 18.8% of patients with a responsive and monophasic course still experienced adverse events. Approximately 26% of LN patients exhibit a responsive and monophasic course. Predicting such a course remains challenging; despite improved outcomes, 18.8% of these patients still experience adverse long-term events.