Coexisting Tubulointerstitial Inflammation and Damage Is a Risk Factor for Chronic Kidney Disease in Patients With Lupus Nephritis

Objective

This study aims to determine whether the concurrent presence of tubulointerstitial inflammation (TII) and tubulointerstitial damage (TID) predicts the progression of chronic kidney disease (CKD) in patients with lupus nephritis (LN).

Methods

Data from 175 LN patients, collected at the time of renal biopsy, were analyzed. Patients were stratified into two groups based on the presence or absence of coexisting TII/TID. Uni- and multivariable Cox proportional hazard regression models were utilized to identify independent risk factors for CKD in LN patients.

Results

Of 175 patients, 110 (62.9%) exhibited coexisting TII/TID, whereas 65 (37.1%) did not. Patients with coexisting TII/TID tended to be older and presented with higher levels of ESR and 24-h proteinuria, as well as lower levels of eGFR and hemoglobin compared to those without coexisting TII/TID. Over a mean follow-up period of 89.9 months, CKD and end-stage renal disease occurred more frequently in patients with coexisting TII/TID. Notably, the presence of coexisting TII/TID was associated with a higher risk of CKD progression, with adjusted hazard ratios of 2.667 (95% CI: 1.333, 5.335, p = 0.006) for all LN patients, 3.265 (95% CI: 1.451, 7.345, p = 0.004) for those with class III, IV, and V LN, and 3.045 (95% CI: 1.289, 7.195, p = 0.011) for those with class III, IV, V LN, and eGFR ≥ 30 mL/min/1.73 m².

Conclusions

LN patients with coexisting TII/TID are at a heightened risk of kidney function deterioration at LN onset and subsequent development of CKD over the long term.