Hematological Markers as Predictors of Attack and Remission Phases in Pediatric Familial Mediterranean Fever

Background: The study aimed to evaluate whether routine hematological parameters can differentiate attack and remission phases in children with Familial Mediterranean Fever (FMF) and to identify accessible biomarkers for disease activity monitoring. Methods: This retrospective study included pediatric FMF patients diagnosed according to Tel Hashomer, Livneh, or Yalçınkaya criteria at Aydın Adnan Menderes University between April 2000 and April 2020. Patients with complete blood count data available for both attack and remission phases were analyzed. Hematological parameters included leukocyte, neutrophil, lymphocyte, and platelet counts, plateletcrit (PCT), mean platelet volume (MPV), and platelet distribution width (PDW). Paired comparisons were performed using appropriate statistical tests. Independent predictors of disease phase were identified using a multivariate mixed-effects logistic regression model. Results: Eighty-seven patients (mean age at diagnosis 7.1 ± 3.6 years) were included. Neutrophil counts were significantly higher during attacks than remission (p < 0.001). Although lymphocyte counts were not significant in univariate analysis, higher lymphocyte concentration was independently associated with remission (OR = 1.71, 95% CI: 1.19–2.45). PDW was significantly higher during remission and independently predicted remission status (OR = 1.92, 95% CI: 1.30–2.85). PCT and MPV were not significant predictors. Conclusions: Neutrophil count, lymphocyte count, and PDW may represent potential and accessible markers associated with FMF attack and remission phases in pediatric patients.