title: Optimal cut-off value for homeostasis model assessment (HOMA) index of insulin-resistance in a population of patients admitted electively in a Portuguese cardiology ward.
abstract: BACKGROUND
  Insulin resistance is the pathophysiological key to explain metabolic syndrome. Although clearly useful, the Homeostasis Model Assessment index (an insulin resistance measurement) has not been systematically applied in clinical practice. One of the main reasons is the discrepancy in cut-off values reported in different populations. We sought to evaluate in a Portuguese population the ideal cut-off for Homeostasis Model Assessment index and assess its relationship with metabolic syndrome.
  
  
  METHODS
  We selected a cohort of individuals admitted electively in a Cardiology ward with a BMI < 25 Kg/m2 and no abnormalities in glucose metabolism (fasting plasma glucose < 100 mg/dL and no diabetes). The 90th percentile of the Homeostasis Model Assessment index distribution was used to obtain the ideal cut-off for insulin resistance. We also selected a validation cohort of 300 individuals (no exclusion criteria applied).
  
  
  RESULTS
  From 7 000 individuals, and after the exclusion criteria, there were left 1 784 individuals. The 90th percentile for Homeostasis Model Assessment index was 2.33. In the validation cohort, applying that cut-off, we have 49.3% of individuals with insulin resistance. However, only 69.9% of the metabolic syndrome patients had insulin resistance according to that cut-off. By ROC curve analysis, the ideal cut-off for metabolic syndrome is 2.41. Homeostasis Model Assessment index correlated with BMI (r = 0.371, p < 0.001) and is an independent predictor of the presence of metabolic syndrome (OR 19.4, 95% CI 6.6 - 57.2, p < 0.001).
  
  
  CONCLUSIONS
  Our study showed that in a Portuguese population of patients admitted electively in a Cardiology ward, 2.33 is the Homeostasis Model Assessment index cut-off for insulin resistance and 2.41 for metabolic syndrome.
  
  
  CONCLUSIONS
  Homeostasis Model Assessment index is directly correlated with BMI and is an independent predictor of metabolic syndrome.
authors.affiliation: Serviço de Cardiologia. Hospital de Santa Marta. Centro Hospitalar Lisboa Central. Lisboa. Portugal.
authors.forename: Ana Teresa
authors.initials: AT
authors.lastname: Timóteo
authors.affiliation: Serviço de Patologia Clínica. Hospital de Santa Marta. Centro Hospitalar Lisboa Central. Lisboa. Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Miranda
authors.affiliation: Serviço de Cardiologia. Hospital de Santa Marta. Centro Hospitalar Lisboa Central. Lisboa. Portugal.
authors.forename: Miguel Mota
authors.initials: MM
authors.lastname: Carmo
authors.affiliation: Serviço de Cardiologia. Hospital de Santa Marta. Centro Hospitalar Lisboa Central. Lisboa. Portugal.
authors.forename: Rui Cruz
authors.initials: RC
authors.lastname: Ferreira
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D016507:Cardiology Service, Hospital; D003430:Cross-Sectional Studies; D005260:Female; D006706:Homeostasis; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000175:diagnosis*; D008875:Middle Aged; D008954:Models, Biological; D011174:Portugal
chemical_list: D001786:Blood Glucose