Strategy for second kidney biopsy in patients with lupus nephritis.

BACKGROUND Standard clinical and laboratory parameters have limited predictive values for discriminating between active lupus nephritis and chronic disease. The objective of this study was to examine the predictive utility of a second kidney biopsy in patients with lupus nephritis. METHODS Patients with lupus nephritis were advised to have second kidney biopsies at the end of the maintenance phase of their therapies. Baseline and second renal biopsies were re-classified by pathologists blinded to the clinical data. The relationships between remission status and histological parameters were examined. RESULTS Included in this study were 77 patients followed up for a median duration of 8.7 years (interquartile range, 5.3-10.1 years). Their renal survival rates were 93% for those in complete remission (CR), 69% for partial remission (PR) and 41% for no remission (NR). One-third of the patients with PR and 14% of patients with NR had no histological evidence of active disease on second biopsy. At the second biopsy, but not at the baseline biopsy, activity index was predictive of survival. The 10-year renal survival rate was 100% for those with an activity index of 0, 80% for those with an activity index of 1 or 2 on the second biopsy and 44% for those with an index of >2, regardless of remission status. CONCLUSION Second kidney biopsy at the end of maintenance phase of therapy is an important diagnostic and prognostic tool that could guide physicians to safer practices with better outcomes.