Evaluation of Predictive Biomarkers for Pulmonary Exacerbations in Cystic Fibrosis

<bold>Objective:</bold> We aimed to evaluate easily available markers, as CRP, CRP/Albumin (ALB) ratio, neutrophil-to-lymphocyte ratio (NLR), derived NLR (dNLR) and systemic immune inflammation (SII) index to determine the pulmonary exacerbation in cystic fibrosis (CF). <bold>Methods:</bold> CRP, CRP/ALB ratio, NLR, dNLR and SII index levels were compared in patients with CF (PwCF) during exacerbation and non-exacerbation periods between 2021-2024. <bold>Results:</bold> Among 54 PwCF, 25 were female and 21 had pulmonary exacerbations. CRP, CRP/ALB ratio, NLR, dNLR and SII index were increased during the exacerbation periods (p<0.01). CRP cut-off value was determined as 6.2 mg/dL (sensitivity of 85%, specificity of 84%). CRP/ALB ratio cut-off value was 1.7 (sensitivity of 81%, specificity of 90%). When cut-off values of NLR, dNLR and SII index were 2.2, 1.15 and 426, sensitivities were 62%, 71% and 86%; specificities were 79%, 66% and 67%, respectively. <bold>Conclusion:</bold> Although CRP is a crucial inflammatory marker for exacerbation, we also anticipate that the value of NLR, dNLR, SII, which can be derived easily from a complete blood count, could serve as significant parameters in predicting exacerbation in PwCF.