Factors associated with chronic renal failure in 121 patients with diffuse proliferative lupus nephritis: a case-control study

Abstract

Lupus nephritis remains an important problem in patients with systemic lupus erythematosus (SLE). Some patients with diffuse proliferative lupus nephritis (DPLN) develop chronic renal failure (CRF). A case-control study was designed to determine the variables associated with CRF in patients with DPLN. We studied 121 patients with biopsy-proven DPLN seen in our institution from 1970 to 1988. There were 34 patients who developed CRF, the remaining were their controls. Clinical charts were reviewed and a pathologist re-scored blindly both activity and chronicity indices. The mean of age at SLE onset was 24.1 ± 7.9 years; the mean disease duration was 9.2 ± 6.1 years for controls and 6.1 ± 5 years for patients. The main variables associated with CRF were male sex, HR (hazard ratio): 12.6 (95% CI 1.6-98.2); activity index, HR 2.59 (1.07-6.3) ; severe infections, HR 2.9 (1.2-7.3); number of antihypertensive drugs, HR 2.5 (1.4-4.7); cellular crescents, HR 1.6 (1.2-2); and interstitial inflammation, HR 2.7 (1.5-5.1). A protective effect was observed with longer use of ≤20 mg of prednisone, HR 0.53 (95% CI 0.34-0.8); azathioprine, HR 0.6 (0.4-0.8); and length of formal education, HR 0.3 (0.09-0.94). Our results indicate that maleness, activity index, extracapillary proliferation and interstitial inflammation, as well as hypertension and severe infections associate with CRF in patients with DPLN, and treatment and higher education, perhaps through better therapeutic compliance, may be protective.