In patients with lupus nephritis, findings from the second kidney biopsy better predict the risk for end-stage kidney disease (ESKD), investigators reported in Lupus Science & Medicine.
Andrea Doria, MD, of the University of Padua in Padova, Italy, and colleagues compared first and second biopsy findings from 92 patients with lupus nephritis. Clinicians ordered a second kidney biopsy after patients experienced nephritic flares (30.4%), proteinuric flares (50%), or lack of complete renal response to therapy (19.5%). The time between the first and second biopsies were 5.1, 4.6, and 4.1 years for the nephritic flare, proteinuric flare, and poor renal response groups, respectively.
Half of patients had a switch in LN class at the second biopsy, typically from non-proliferative to proliferative classes, the investigators reported. Class IV disease remained stable in over 50% of cases.
ESKD developed in 25 patients (27.2%), including 60.7% of the nephritic flare group. At second biopsy, the nephritic flare group had significantly lower estimated glomerular filtration rate, significantly higher serum creatinine, and more class IV disease than the other 2 groups.
At second biopsy, activity index of 2 or more, chronicity index greater than 4, and 24-hour proteinuria level of 3.5 g/d or more significantly predicted a 20%, 41%, and 22% increased risk for ESKD, respectively, Dr Doria’s team reported. The investigators found that glomerular activity and tubular chronicity correlated the most with ESKD risk. No histological or laboratory results from the first biopsy predicted ESKD, although arterial hypertension did.
“Because an increased [activity index] at second biopsy signified an increased risk in ESKD, this highlights the importance of performing a second kidney biopsy in patients with suboptimal/no response or flaring LN as a tool for long-term risk stratification, regardless of LN class [change],” Dr Doria’s team wrote.
Gatto M, Radice F, Saccon F, et al. Clinical and histological findings at second but not at first kidney biopsy predict end-stage kidney disease in a large multicentric cohort of patients with active lupus nephritis. Lupus Sci Med. Published May 9, 2022. doi:10.1136/lupus-2022-000689