#3380 The association between estimated glomerular filtration rate (eGFR) and disability worsening in patients with multiple sclerosis

Abstract Background and Aims Multiple sclerosis (MS) is a chronic autoimmune neurological disease characterized by focal demyelinated lesions of the central nervous system, leading to heterogenous neurological impairments. In recent years, emerging evidence suggests a complex interrelation between MS and kidney disease. While renal abnormalities are common in individuals with MS, there are no data concerning the impact of kidney function on MS disability progression. Therefore, the aim of the study was to investigate the association between the baseline level of kidney function and disability worsening in patients with MS. Method This prospective observational study enrolled 373 MS patients (mean age: 44.2 ± 11.4 years; 242 (64.89%) females). Confirmed disability worsening (CDW) was defined as an increase in the Expanded Disability Status Scale (EDSS) score by at least 1 point from baseline, sustained between 2 follow-up visits separated in time by no less than 6 months (or by 1.5 points if the EDSS score at baseline was 0, or by 0.5 points if the baseline EDSS score was ≥5.5). Kidney function was assessed by estimated glomerular filtration rate (eGFR) calculated by the CKD-EPI equation. Socio-demographic, clinical and biological data were analyzed with logistic uni- and multivariable regression methods to investigate their association with CDW. A two-tailed value <0.05 was considered significant. Results During a median follow-up period of 10 years, a total of 109 patients (29.22%) developed CDW. Individuals with CDW presented an older age at MS onset (median age of onset 37 years vs. 26 years, P = 0.0002), lower baseline median eGFR (89.8 ml/min/1.73 m2 vs. 116 ml/min/1.73 m2, P < 0.001), higher baseline median EDSS score (3.5 vs. 1, P = 0.001), and a higher prevalence of secondary-progressive MS (SPMS) phenotype (3.67% vs. 0.38%, P = 0.027), as compared to non-CDW patients. In univariate regression analysis, the CDW was associated with age of MS at onset (OR = 1.04; 95% CI: 1.02 to 1.06, P = 0.001), baseline EDSS score (OR = 1.16; 95% CI: 1.04 to 1.03, P = 0.009), baseline eGFR (OR = 0.97, 95% CI: 0.96 to 0.98, P < 0.001), and the SPMS phenotype (OR = 9.98; 95% CI:1.1 to 90.34, P = 0.041). In multivariate analysis, baseline eGFR remains an independent predictor for the risk of CDW (OR = 0.97, 95% CI: 0.95 to 0.98, P < 0.0001, Nagelkerke R2 = 0.110). Conclusion This study showed that a lower baseline eGFR contributed to disability worsening in MS patients. The relationship between kidney function and disability risk in MS should be further investigated to improve disease prognosis and quality of life for MS patients.