Complete remission in severe lupus nephritis: assessing the rate of loss in proteinuria

The prognosis of severe lupus nephritis (SLN) is improved in patients attaining a complete remission (CR). The time to remission ranges from 10 to 16 months with many patients not attaining a CR until after 12 months. We assessed whether the rate of loss in proteinuria (UPro) is predictive of a CR in SLN patients.

We studied 85 adult patients in the prospective controlled trial of plasmapheresis in SLN (New England Journal of Medicine 1992). All patients had International Society of Nephrology/Renal Pathology Society Class IV±Class V lesions. All patients received prednisone and oral cyclophosphamide and 39 patients received plasmapheresis. A CR was defined by a serum creatinine (SCr) of ≤1.4 mg/dL and UPro of ≤0.33 g/day. The change in UPro in gram per day per week was determined at 3 and 6 months from entry to the study.

A CR was attained in 37 patients (44%) by 16±14 months. The level of UPro at baseline was similar in CR and no remission (NR) patients (5.5 versus 6.4 g/day), but CR patients had a lower SCr (1.2 versus 2.4, P<0.0001). At 6 months, the rate of change of UPro was higher at (-)0.224 g/day/week in CR patients and (-)0.107 g/day/week in NR patients (P=0.01) and a 50% reduction in UPro was seen in 78% of CR patients but only 42% of NR patients (P=0.009). The time to a CR was ≤12 months in 19 patients and >12 months in 18 patients. The baseline SCr was similar among the two groups. However, UPro at baseline was lower in patients with CR in ≤12 months (3.9±2.7 versus 7.2±3.0 g/day, P=0.001) but the proportion of patients with membranous glomerulonephritis was similar (16 versus 22%). The rate of change in UPro at 6 months was similar at (-)0.214 g/day/week in patients with CR ≤12 months and (-)0.235 g/day/week in those with CR>12 months (P=0.6). At 6 months, a 50% reduction in UPro was also similar in the two groups (84 versus 72%, P=0.4). Additionally, the rate of change in UPro at 3 and 6 months was similar within each group.

The rate of change in proteinuria at 6 months is significantly greater in patients attaining a CR relative to NR patients but similar in patients with a CR in ≤12 months or >12 months. Thus, the rate of loss of UPro at 6 months may help in predicting which patients will attain a CR.