Clinical and laboratory features of 496 cases of biopsy-proven lupus nephritis; a study at Shiraz University of Medical Sciences, Iran

Abstract

Introduction: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that can involve various organs. Renal involvement has been seen in about 60% of SLE patients, while the most common presentation of lupus nephritis (LN) is proteinuria. Objectives: This study aimed to investigate the clinical and laboratory features of LN patients, confirmed by kidney biopsy and compare these among different classes of LN. Patients and Methods: This cross-sectional study was conducted on clinical and laboratory data of patients with LN from 2001 to 2016. All patients diagnosed with definite LN by biopsy and electron microscopy (EM) were included in this study. Results: A total number of 496 patients were enrolled. The mean age of all patients was 28.32 ±11.41 years; 82.4% (409) were females. The biopsies were classified into LN classes II, III, IV, V, and VI, whose frequencies were 98 (20.6%), 93 (19.5%), 225(47.3%), 46 (9.7%), and 14 (2.9%), respectively. Tubular atrophy (P<0.001) and interstitial fibrosis (P<0.001) were found to be significantly associated with classes of LN. Additionally, 72.7% (8) and 48.2% (92) of patients in classes Ⅵ and Ⅳ of LN had blood urea nitrogen (BUN) levels more than the normal range (P< 0.001). Regarding serum creatinine levels, 81.8% (9) and 42.9% (81) of patients in classes Ⅵ and Ⅳ of LN had high levels (P<0.001). Moreover, nephrotic syndrome (NS) was reported in 47.5% (47) of patients with class Ⅱ of LN followed by 38.8% (36) in class Ⅲ. Besides, edema was significantly more dominant in classes Ⅳ (74.3%, 133) and VI (75%) of LN patients (P=0.03). Conclusion: Tubular atrophy and interstitial fibrosis were more commonly seen in LN class Ⅵ followed by class IV. Edema, hypertension, and proteinuria are common presentations in class IV. Complete assessment of renal biopsy is still helpful for the definite classification of LN.