Predictors of mortality in children with lupus nephritis

Abstract

Background Renal involvement during the clinical course of systemic lupus erythematosus (SLE) is generally considered to be the most important factor influencing disease prognosis in terms of morbidity and mortality. Various factors have been reported to influence the prognosis of lupus nephritis (LN). Objective To analyze clinical signs and laboratory parameters that might serve as predictors associated with mortality in pediatric LN. Methods Retrospectively, medical records of children with LN at Soetomo Hospital from 1998 to 2011 were studied. Diagnosis of SLE was based on Revised American Rheumatism Association critera, while patients with clinical manifestations of hypertension, abnormal urinalysis, and serum creatinin > 1 mg/dL were considered as lupus nephritis. Cox proportional hazard modeling was used to assess for associations of clinical signs and laboratory parameters with mortality. Kaplan-Meier survival analysis was used to assess the cumulative survival from the time of diagnosis to the outcome. Results There were 57 children with LN of whom 43 (75%) were girls. The female-to-male ratio was 3:1. Subjects’ mean age was 10.6 (SD 6.87) years. The mean time of observation was 51 (SD 74.54) months and 23 (40%) children died. Age, gender, hypertension, hematuria, proteinuria, and anemia were not significant as predictors for mortality. However, hypertensive crisis (HR=2.79; 95%CI 1.16 to 6.75; P=0.02) and initial glomerular filtration rate (GFR) of <75 mL/min/1.73m2 (HR=3.01; 95%CI 1.23 to 7.34; P=0.01) were significant predictors of mortality in children with LN. The mean survival time of LN with hypertensive crisis and initial GFR <75 mL/min/1.73m2 was 36.9 (SD 12.17) months. Conclusion Hypertensive crisis and GFR <75 mL/min/1.73m2 are significant predictors of mortality in children with LN.

Keywords

• pediatric lupus nephritis, hypertensive crisis, low GFR, SLE