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.