Background Several prognostic factors have been described in lupus nephritis, which vary depending on the population studied. Few studies have examined these factors in relation to different stages of treatment.
Objectives To identify prognostic factors associated with response to induction therapy in LN according to the stages of treatment.
Methods We performed a retrospective case-control study nested in a cohort of patients with systemic lupus erythematosus (SLE) with biopsy-proven LN according to WHO, in a period from January 2001 to December 2008. All patients received induction therapy remission and had a minimum follow-up period of two years. Patients were divided in 2 groups: group 1, responders (presence of inactive sediment, proteinuria <0.5 g/day, and estable renal function) and group 2: non-responders (active sediment, proteinuria >0.5 g/day, and decrease renal function) at 6, 12, and 24 months. We analyzed 18 clinical and laboratory variables that potentially have predictive value for response to therapy including age, gender, duration of SLE, duration of LN, histologic type, delay in treatment, biochemical (serum creatinine, urinary active sediment, creatinine clearance, proteinuria), and immunological parameters (complement C3, C4 and anti-dsDNA antibodies). We identified predictors of therapeutic response at 6, 12 and 24 months by univariate and multivariate analysis; odds ratios (OR) with confidence intervals (CI) 95% were also calculated.
Results We reviewed clinical records of 168 patients, 141 of female (84%), with average age at diagnosis of LN of 30.4±10.6 years, the mean time of evolution of SLE until LN diagnosis was 28.0±48.8 months. LN was initial manifestation of SLE in 94 (56.5%) patients, renal biopsy showed: type II in 33 patients (19.6%), class III in 28 (16.6%), class IV in 92 (54.7%), class V in 7 (10.2%) and a combination in 7 (10.2%). One-hundred and thirteen (67%) patients received pulses of cyclophosphamide as induction therapy, the response rate was 69% at 6 months, 86.9% at 12 months and 79.7% at 24 months. Multivariate analysis with lack of therapeutic response as the dependent variable is shown in the following table:
Conclusions The main predictor of poor therapeutic response at 24 months is the delay in treatment. At 12 months is low creatinine clearance. Patients younger than 25 years and microhematuria are the best responders to treatment at 6 months. Male gender and elevated creatinine and hypocomplementemia were not factors of poor therapeutic response. Early treatment of lupus nephritis is associated with favourable response to two years.
Disclosure of Interest None Declared