Renal thrombotic microangiopathy impairs renal function recovery in lupus nephritis

Renal thrombotic microangiopathy (TMA) remains a challenge for lupus nephritis (LN) patients. The purpose of this study was to determine the prognostic significance of renal TMA in patients with LN.

Patients were recruited from the LN database (http://ln.medidata.cn) of the First Affiliated Hospital of Sun Yat-Sen University between 2001 and 2023. To assess the association between renal TMA and kidney recovery outcomes, propensity score matching (PSM), and Cox proportional hazards regression analysis were used.

5.17% LN patients had kidney biopsies showing TMA. After PSM, patients with renal TMA exhibited lower scores on the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and the Activity Index (AI) scores in renal biopsies. Renal TMA was independently associated with deteriorated renal function recovery compared with non-renal TMA [hazard ratio (HR) 0.62; 95% confidence interval (CI) 0.42-0.94, P = .022). This association remained significant after PSM (HR: 0.50; 95% CI: 0.31-0.82, P = .004). Additionally, renal TMA was independently associated with higher risk of renal replacement therapy (RRT) (HR: 6.90; 95% CI: 3.57-13.30, P < .001) in LN patients. The proportion of glomerulosclerosis is a predictive factor for renal function recovery in LN patients with renal TMA (HR: 0.62; 95% CI: 0.40-0.95, P = .027).

Renal TMA is strongly associated with poorer renal function recovery in LN patients. Furthermore, a higher degree of glomerulosclerosis is a significant risk factor for impaired recovery in these patients.