Abstract / Summary
Abstract Background Subclinical inflammation may continue during clinical remission in children with familial Mediterranean fever (FMF), contributing to amyloidosis risk. Serum amyloid A (SAA) is a standardized marker of inflammation; however, its availability may be limited. Complete blood count (CBC)-derived indices are inexpensive surrogate biomarker, although their performance during remission remains uncertain. Objective To compare seven CBC-derived indices for identifying persistent subclinical inflammation and assess their independence from disease severity. Methods Clinical and laboratory data during remission were retrospectively analyzed in 182 children with FMF. Subclinical inflammation was defined as SAA > 10 mg/L. NLR, PLR, LMR, MLR, dNLR, SII, and SIRI were calculated from CBC. Disease severity was assessed using the International Severity Scoring System for FMF (ISSF). Results Sixty-nine children (37.9%) had elevated SAA. SIRI was higher in this group (P = 0.027) and showed the highest but modest discriminatory performance (AUC = 0.598; 95% CI, 0.514–0.681). Its association with elevated SAA became borderline after adjustment for disease severity (adjusted OR = 1.61; 95% CI, 0.99–2.63; P = 0.055), whereas disease severity was the only independent predictor (adjusted OR = 3.66; 95% CI, 1.73–7.76; P = 0.001). Conclusion SIRI showed the strongest overall performance but limited discriminatory accuracy and should not replace SAA. Disease severity was the principal independent determinant of persistent subclinical inflammation.