Correlations of baseline neutrophil-lymphocyte ratio with prognosis of patients with lupus nephritis: A single-center experience.

Objective: We aimed to evaluate the correlations among the neutrophil-to-lymphocyte ratio (NLR), lupus nephritis (LN) clinical characteristics, and renal prognosis of patients with LN.

Methods: We enrolled 122 patients who were diagnosed with LN at the Rheumatology Department of the People's Hospital, Xinjiang Uygur Autonomous Region from January 2013 to April 2022. We determined the occurrence of renal adverse events in patients with LN by reviewing medical records and follow-up data. Correlations were analyzed using the Spearman test, and the quartile method was applied to classify all of the 122 patients who had completed follow-up into low, medium, and high NLR groups. The Kaplan-Meier survival curve was used to conduct survival analysis, and Cox regression analyses were used to explore possible potential risk factors.

Results: The baseline NLR of patients with LN was positively correlated with C-reactive protein (CRP), serum creatinine, blood urea nitrogen, and systemic lupus erythematosus disease activity index scores (P < 0.05) and negatively correlated with estimated glomerular filtration rate (eGFR) and serum albumin (P < 0.05). Patients who completed follow-up were divided into three NLR groups based on their NLR values: 30 in the low (NLR ≤ 2.21), 62 in the medium (NLR > 2.21 and NLR ≤ 6.17), and 30 in the high NLR group (NLR > 6.17). The patient survival time before developing poor renal prognosis was significantly different among the three groups (P < 0.05). High NLR (hazard ratio [HR] = 3.453, 95% confidence interval [CI]: 1.260-9.464), CRP (HR = 1.009, 95% CI: 1.002-1.017), eGFR (HR = 0.979, 95% CI: 0.963-0.995), and 24-h proteinuria values (HR = 1.237, 95% CI: 1.025-1.491) as well as anti-double stranded DNA antibody positivity (HR = 3.056, 95% CI:1.069-8.736) were independent risk factors associated with a poor renal prognosis for patients with LN.

Conclusion: The baseline NLR in peripheral blood can be used as a reference index for evaluating renal function and disease activity in patients with LN, and a high NLR has predictive value for the prognosis of patients with LN.