Evolution of chronic kidney disease in patients with systemic lupus erythematosus over a long-period follow-up: a single-center inception cohort study

The objective is to investigate the accrual rate and risk factors of chronic kidney disease (CKD) in an inception cohort of patients with systemic lupus erythematosus (SLE) followed at a single tertiary center. A prospectively collected database of 256 consecutive patients with SLE followed over a 25-year period was systematically interrogated for demographic, disease manifestations, co-morbidities, and outcome. Standardized SLE activity and damage scores were determined for the first and last study visits, and estimated glomerular filtration rate (eGFR; MDRD formula) was calculated at the time of diagnosis and at each year of the follow-up. CKD was defined as eGFR < 60 ml/min/1.73 m(2). Results were analyzed with univariate and multivariate models and Kaplan-Meier curves, as appropriate. The cohort was predominantly female (90 %) and Jewish (91.1 %). Mean age at diagnosis was 38 +/- 15.5 years, mean SLE activity score 6.4 +/- 3.8, mean disease duration 8.8 +/- 6.6 years, and mean damage score 0.2 +/- 0.6. Seventy-five patients (30.8 %) were diagnosed with American College of Rheumatology (ACR)-defined lupus renal disease during the study period. There was a progressive decrease in eGFR over time. The prevalence of CKD was 46.7 % in patients with ACR-defined renal lupus disease and 16.4 % in those without. The hazards ratio for CKD was significantly higher in patients with lupus nephritis (LN) than without (p < 0.001). Earlier CKD was positively associated with hypertension (p = 0.01), older age at diagnosis (p = 0.01), and LN (p < 0.001), and negatively associated with hydroxychloroquine treatment (p < 0.001). The prevalence of CKD increases cumulatively in patients with SLE, also in those without overt lupus renal disease. Lupus renal disease poses a significant hazard for earlier development of CKD, and hypertension is a major risk factor for patients with and without nephritis. Antimalarial treatment is associated with renal preservation only in patients with lupus nephritis.