Objective: The recovery time from abnormal levels of proteinuria with standard treatment in longitudinal studies of patients with systemic lupus erythematosus has not been well described. We aimed (1) to determine the recovery time from proteinuria in patients with lupus nephritis (LN) receiving standard treatment, and (2) to determine whether the initial level of proteinuria predicts time to improvement.
Methods: We studied all patients with LN recorded in the database from 1970 until 2011. Proteinuria was defined as ≥0.5 g/24 h. Patients were grouped as follows: group 1 having 0.5-0.9 g/day, group 2 having 1-1.9 g/day, and group 3 having ≥2 g/day. Recovery from proteinuria was defined as proteinuria<0.5 g/24 h. Time to recovery from proteinuria was studied with the Kaplan-Meier curves. Factors associated with proteinuria recovery were evaluated using proportional hazard models.
Results: Among the 212 patients studied, 52% recovered from proteinuria within 2 years and an additional 22% recovered within 5 years, for a total of 74%. The level of proteinuria at baseline visit predicted the time to improvement. Patients with a higher level of proteinuria at baseline needed a longer time to normalize their proteinuria. Male sex, hypocomplementemia, high level of proteinuria at diagnosis of LN, and disease duration>5 years at onset of LN each independently predicted late recovery of proteinuria and had an effect on the percentage of patients who recovered.
Conclusion: The tempo of recovery from proteinuria in LN is slow and the level of proteinuria at baseline visit predicts the time to complete recovery.
Keywords: KIDNEY BIOPSY; LUPUS NEPHRITIS; SYSTEMIC LUPUS ERYTHEMATOSUS.