Prevalence, Risk Factors, and Outcomes of Chronic Kidney Disease in Systemic Lupus Erythematosus Patients with and without Lupus Nephritis.

OBJECTIVE Chronic kidney disease (CKD) has significant clinical and therapeutic implications. This study assesses CKD prevalence, risk factors, and long-term outcomes in systemic lupus erythematosus (SLE) with and without lupus nephritis (LN). METHODS This single-center, retrospective medical records review study (2014-2023) included adult SLE patients. CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73m2 or albuminuria ≥30 mg/24h in at least two consecutive tests, spaced ≥ 3 months apart. Statistical analyses included chi-squared tests, t-tests, multivariable regression, and Cox proportional hazards models. RESULTS 175 SLE patients were included with a mean follow-up of 18.3±14.7 years; 12 required kidney replacement therapy. CKD was diagnosed in 54.6% (89/163) of patients, including 15.7% with reduced eGFR only, 52.8% with albuminuria only, and 31.5% with both. LN was associated with a higher hazard ratio (HR=5.4) for CKD. Nevertheless, 46.1% of CKD patients had no history of LN. CKD was associated with increased cardiovascular morbidity, hospitalization rates for SLE exacerbations and infections. Cox analyses identified LN as the strongest predictor of CKD; other predictors were age and lower eGFR at diagnosis. CKD was an important predictor of mortality among patients with lupus, both in univariate and multivariable analyses (19.1% vs. 1.4%, p<0.001). CONCLUSION CKD is highly prevalent in SLE, including in patients without prior LN. CKD is associated with increased morbidity and mortality. This study emphasizes the clinical relevance of CKD diagnosis and management in SLE patients.