Early Kidney Biopsy Necessary During Early-Onset Urinary Abnormalities to Detect Lupus Nephritis

Early kidney biopsies are critical for the detection of lupus nephritis (LN), even among patients with low-grade proteinuria, as they may still manifest severe forms of LN, according to study results published in Clinical Rheumatology.

Investigators conducted a retrospective cross-sectional cohort study to examine the histopathological findings in initial kidney biopsies among patients with systemic lupus erythematosus (SLE) and suspected LN. They concentrated on identifying and analyzing histopathological discoveries unrelated to LN.

The investigators included a total of 139 patients with SLE who had their first kidney biopsy performed between 1995 and 2021. The patients were divided into 2 groups, LN and non-LN, based on histological findings, which were compared with clinical and laboratory features.

The majority of the patients included were women (76.3%) and had a median age of 34.5 years. Patients without LN were diagnosed with SLE at an older age compared against patients with LN (average age 38.0 vs 30.1; P =.013). Additionally, patients in the non-LN group had a longer disease duration (mean duration, 11.9 vs 0.5 years; P =.027).

During kidney biopsy, 69.4% of patients were prescribed oral corticosteroids, while 18.2% were prescribed immunosuppressants.

Of the 139 patients, 123 (88.5%) displayed findings that aligned with International

Society of Nephrology/Renal Pathology Society classification for the presence of LN. Conversely, the remaining 16 patients (11.5%) exhibited findings that did not correspond with LN.

Among patients with severe LN histotypes (class III/IV), 20% showed the presence of low-grade (<0.5 g/24 h) proteinuria.

Among the non-LN group, 85.7% satisfied the SLE International Collaborating Clinic criteria for renal SLE, compared with 94.7% in the LN group. In terms of the American College of Rheumatology/European Alliance of Associations for Rheumatology criteria, 66.7% of the non-LN group fulfilled the criteria for LN compared with 74.8% of patients in the LN group.

This study was limited by its retrospective design, which relied on the availability of renal and immunological measurements. These measurements may vary over time due to changing laboratory methods.

The study authors concluded, “Thus, biopsies should be performed early and current guidelines for performing kidney biopsies, and the classification criteria for LN seem to be insufficient in clinical practice.”