Prognostic relevance of persistent haematuria in patients with lupus nephritis

Background and Hypothesis This study aimed to investigate the significance of persistent haematuria in lupus nephritis. Methods A total of 178 patients with lupus nephritis were enrolled and regularly followed up from December 2016 to September 2022. Follow-up duration was from LN diagnosis to the patient’s latest visit, or terminated at the onset of endpoint events if they occurred. And their clinical and laboratory data as well as outcomes were monitored and analyzed from the enrollment point until the final visit. Results 138 out of 178 (77.5%) patients with lupus nephritis presented with haematuria at initial diagnosis. During follow-up, 34 patients (19.1%) had no haematuria, 72 (40.4%) patients initially diagnosed but later resolved and 66 (37.1%) exhibited persistent haematuria. Furthermore, patients with persistent haematuria showed higher SLEDAI scores (12.3 ± 2.9 vs 10.7 ± 3.6, P=0.002), lower hemoglobin (92.7±25.4 vs 102.0±21.1, g/L, P=0.010), albumin (24.9 ± 6.8 vs 27.5 ± 7.6, g/L, P=0.024), and decreased C3 (0.4(0.3, 0.5) vs 0.5(0.3, 0.6), g/L, P=0.009) and C4 (0.1(0.0, 0.1) vs 0.1(0, 0.1), g/L, P=0.012), and elevated blood urea nitrogen and serum creatinine ([8.9(6.7, 14.8) vs 5.7(4.4, 8.8)] mmol/L, [90.0 (64.5, 132.3) vs 62.0 (48.0, 80.0)] μmol/L, all P<0.001) compared to those without persistent haematuria (n=106). In time-dependent Cox proportional hazards regression models, persistent haematuria exhibited a significant overall time-averaged effect on composite clinical endpoints, with an adjusted HR of 3.40(95% CI: 1.06–10.90; P = 0.039). Notably, this risk effect was not fixed but showed an increasing trend over time — at 12 months of follow-up, the risk of adverse outcomes in patients with persistent hematuria had elevated to 10.37-fold. Conclusions Almost 37.1% exhibited persistent haematuria in lupus nephritis. Furthermore, persistent haematuria independently predicted adverse outcomes, with significantly higher risks for all-cause mortality and progression to renal replacement therapy.