PREDICTOR OF RENAL SURVIVAL IN LUPUS NEPHRITIS IN KOREA

Abstract

Background Lupus nephritis (LN) is one of the major manifestations of systemic lupus erythematosus (SLE) which need aggressive immunosuppressive treatments.

Objectives The aim of this study was to investigate whether response rate was different between therapeutic modalities therapeutics for LN, and to study the clinical factors predisposing to poor out-come in patients with lupus nephritis.

Methods One hundred sixth nine patients with LN on biopsy, who followed up more than at least 6 months after diagnosis, were included from seven rheumatology centers in Korea between 2000 and 2010. We retrospectively analyzed the clinicopathologic data using WHO or ISN/RPS, therapeutics, and responses based on 2006 ACR remission criteria. Poor outcome was defined as chronic renal failure (GFR < 60 ml/min) or persistent hemodialysis.

Results The mean age at the time of diagnosis of LN was 31.2 years and a mean of 41.7 ± 2.3 months was followed. One hundred ninety five patientswere performed renal biopsy. The proportion of class II, III, IV, and V was 14 (8%), 58 (34%), 63 (37%), and 34 (20%), respectively. Some patients showed mixed pathology (II+V in 2, III+V in 32 and IV+V in 20). Induction therapeutic modalities were different between classes of LN; the most common therapeutics for class IV was cyclophosphamide NIH regimen [CYC(NIH)] 50%, followed by mycophenolate mofetil (MMF) 33% and CYC Euro regimen [CYC(EUR)] 13%, in contrast to CYC(NIH) 41%, and azathioprine (AZA) 24% for class III, and cyclosporine(CS) 47%, and CYC(NIH) 21%] for class V. In addition, therapeutics for maintenance were also different between classes; MMF 42.2% and AZA 22% for class IV, AZA 43% and MMF 25% for class III, and CS 44% and MMF 20% for class V. Complete or partial response after induction therapy was achieved in 83%, 74%, and 79% of patients with class III, class IV, and class V, respectively. The response rate between induction therapeutics for LN classes was not significantly different. Failure of induction therapy (OR 19.8, p = 8.70 x 10-6) and 1-year response (OR 11.0, p = 9.09 x 10-3) were significantly associated with poor outcome (chronic renal failure or persistent hemodialysis). Failure to achieve remission at 1-year after induction therapy was the risk factor associated with poor renal outcome (OR 35.9, p = 0.026), adjusted by age of LN, disease duration, sex, GFR at diagnosis of LN, proteinuria, and diffuse proliferative LN class (IV or IV+V).

Conclusions Decision among several therapeutic modalities for LN was largely dependent on class of LN on biopsy. Response to current therapeutics for each class of LN was favorable, regardless of therapeutic regimens. With appropriate induction therapy according to baseline renal function and histological class, 1-year response following induction therapy was the most important predictor for renal survival.