Choroidal thickness in active lupus nephritis

Background Lupus choroidopathy was reported to be a marker of severe systemic erythematosus (SLE) activity and is frequently associated with nephropathy. However, it remains controversial whether choroidal thickness (CT) reflects glomerular vascular involvement or provides reliable indirect evidence of lupus nephritis (LN) activity. Therefore, the purpose of the present study was to assess the choroidal thickness in patients with active LN prior to the induction treatment and compare it with a healthy control group. Methods This case-control cross-sectional study evaluated 28 consecutive active LN patients before treatment initiation. All patients fulfilled the 2019 ACR/EULAR classification criteria for SLE, and LN was defined according to the American College of Rheumatology. Kidney biopsy-confirmed LN was present in 20 patients, with classification based on Renal Pathology Society/International Society of Nephrology standards. Health control group balanced by sex and age were included. CT was measured using the enhanced depth imaging protocol on spectral-domain optical coherence tomography. Results LN patients and controls had comparable median age ( p = 0.445) and female predominance ( p = 0.295). Renal parameters were characterized by median creatinine (0.80 ± 0.26 mg/dL) and elevated median protein/creatinine ratio (1.84 ± 1.70 g/g). Histological classes were predominantly proliferative [14/20 (70%)]. The mean central subfoveal CT was significantly lower in LN patients compared to the health control (297 ± 41.7 μm vs 329 ± 69.9 μm, p = 0.004). Conclusion The observed thinning of central subfoveal CT in patients with active LN prior to treatment suggests that the choroid may serve as a subclinical target organ affected by systemic inflammation. Given its non-invasive accessibility, CT measurements may represent a promising tool for monitoring LN activity. Future longitudinal studies are warranted to determine its utility as a biomarker in the clinical management and follow-up of LN patients.