Isolated Hematuria in SLE Patients and its Association with Proteinuria, Urinary Cast and SLE Disease Activity

Abstract: Isolated hematuria and its association with proteinuria, and urinary cast and systemic lupus erythematosus (SLE) disease activity, and decision for renal biopsy is a dilemma for physician in SLE patients. The aim of this study was to investigate 1. whether isolated hematuria is associated with active SLE, 2. to determine duration between hematuria and proteinuria and urinary cast, and 3. to determine renal histological type in SLE patients with isolated hematuria. All episodes of isolated hematuria between 1981 and 1997 were identified from Lupus Unit, Rheumatology Research Center database. Isolated hematuria was defined as >5 RBC/hpf in the absence of urinary infection and other renal manifestations. Relation of hematuria was assessed with proteinuria and urinary cast and SLE disease activity. Needle renal biopsy was done in 19 SLE patents with isolated hematuria. 4.42% (31/700) of our cohort had at least one episode of isolated hematuria. Out of 31 patients in whom the isolated hematuria was the first documented renal manifestation, 11 patients (35.48%) developed another renal manifestation (25.8% proteinuria and 9.67% casts). 54.54% (6/11) of patients developed proteinuria and urinary cast within 3 months. The mean time for development of a second renal manifestation for the patients with isolated hematuria was 19.9 months. Renal needle biopsy was performed for 19 patients (5.78% type IV, 63.15% type III and 21.50% type II). The results of the present study indicate that isolated hematuria is not rare in SLE patients. Also, there was no significant relationship between isolated hematuria and anti ds-DNA, C3, C4 and major organ involvement in patients with SLE. Our study suggests that SLE patients who have isolated hematuria should undergo renal biopsy and that isolated hematuria should be considered a manifestation of active renal SLE. © 2009 Tehran University of Medical Sciences. All rights reserved. Acta Medica Iranica 2009; 47(1): 5-8.