Association of the Pan-Immune-Inflammation Value with Persistent Proteinuria in Patients with Familial Mediterranean Fever

Background and Objectives: Persistent proteinuria is an important marker of renal involvement in familial Mediterranean fever (FMF). This study investigated the association between the pan-immune-inflammation value (PIV) and persistent proteinuria, evaluated the discriminatory performance of PIV, the neutrophil-to-lymphocyte ratio (NLR), and monocyte-to-HDL cholesterol ratio (MHR), and identified factors independently associated with persistent proteinuria. Materials and Methods: This retrospective cross-sectional study included 190 adults with FMF and 150 healthy controls. Persistent proteinuria was defined as a spot urine protein-to-creatinine ratio (UPCR) > 20 mg/mmol confirmed on at least two measurements obtained at least 1 week apart. PIV quartile analysis, Spearman correlation, ROC analysis, and multivariable logistic regression were performed. Results: Persistent proteinuria was present in 62 (32.6%) patients with FMF. Its prevalence increased progressively across PIV quartiles (p for trend < 0.001), and PIV was positively correlated with UPCR (ρ = 0.298, p < 0.001). PIV showed an AUC of 0.774, compared with 0.658 for NLR and 0.654 for MHR. In multivariable analysis, PIV (OR 1.006, 95% CI 1.002–1.009, p = 0.001) and homozygous M694V genotype (OR 3.39, 95% CI 1.46–7.86, p = 0.004) were independently associated with persistent proteinuria. Conclusions: PIV and homozygous M694V genotype were independently associated with persistent proteinuria. PIV may serve as an adjunctive biomarker for the assessment of persistent proteinuria in patients with FMF, although prospective multicenter studies are needed to determine its clinical utility.