Evaluation of the controlling nutritional status score and prognostic nutritional index in patients with familial Mediterranean fever.

Objective: Familial Mediterranean fever (FMF) is the most common disease that leads to secondary amyloidosis in Turkish population. The prognostic nutritional index (PNI) and the controlling nutritional status (CONUT) score were recently investigated in many clinical conditions as predictors of disease activity and prognosis of underlying disease. We aimed to evaluate these indexes in FMF patients.

Methods: We included a total of 135 patients with FMF without amyloidosis at baseline. Demographic characteristics, particular attack features, treatment modalities, disease complications of patients, and a follow-up time for each patient were obtained. Disease complications were defined as amyloidosis or end stage renal disease. Baseline laboratory parameters in the attack-free period were used to assess the subclinical inflammation. Spearman's rho correlation analysis was used for numerical variables. Univariate and multivariate logistic regression analyses were used to determine factors that had an impact on the development of amyloidosis. Receiver operating characteristic (ROC) curve analysis was used to discover the appropriate cutoff points of CONUT score and PNI for predicting the development of amyloidosis.

Results: ROC analysis revealed that the optimal cutoff points for neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), CONUT score, and PNI were >1.9, >145, >2, and ≤54, respectively. The area under the curve values of CONUT score and PNI for predicting the development of amyloidosis were 0.830 (95% CI: 0.76-0.89, P < .001) and 0.940 (95% CI: 0.88-0.97, P < .001), respectively. Correlation analyses revealed significant positive correlations between CONUT score, NLR, and PLR. The high CONUT score was associated with the development of amyloidosis in FMF patients in addition to age and M694V homozygous mutation.

Conclusion: Low PNI and high CONUT score at diagnosis may have a poor prognostic value for the development of amyloidosis in patients with FMF in addition to older age and M694V homozygous mutation. These indexes may be a useful and inexpensive screening biomarkers in clinical practice for predicting amyloidosis in patients with FMF.