title: Performance of glycated haemoglobin (HbA1c) as a screening test for diabetes and impaired glucose tolerance (IGT) in a high risk population--the Brazilian Xavante Indians.
abstract: OBJECTIVE
  To examine the properties of HbA1c to detect diabetes and IGT in adult Brazilian Xavante Indians, a high risk population for diabetes.
  
  
  METHODS
  The survey was carried out between October 2010 and January 2012 and based on a 75 g oral glucose tolerance test (OGTT). Basal and 2h capillary glycaemia were measured by HemoCue Glucose 201+; HbA1c using an automated high-performance liquid chromatography analyzer (Tosoh G7).
  
  
  RESULTS
  630 individuals aged ≥ 20 years were examined and 80 had a previous diagnosis of diabetes. Sensitivity, specificity and accuracy for HbA1c ≥ 6.5% (≥ 48 mmol/mol) were 71.3%, 90.5% and 87.2%. The areas under the ROC curve (AUC) was 0.88 (95%CI: 0.83-0.93). To identify IGT, HbA1c values between 5.7% and 6.4% (39-47 mmol/mol) presented sensitivity, specificity and accuracy of 87.2%, 24.7% and 51.4%, with an AUC of 0.62 (95%CI: 0.57-0.67).
  
  
  CONCLUSIONS
  The ADA/WHO proposed cut-off of 6.5% (48 mmol/mol) for HbA1c was adequate to detect diabetes among the Xavante. However, the performance of the ADA proposed cut-off points for pre-diabetes, when used to detect IGT was inadequate and should not be recommended.
authors.affiliation: Department of Social Medicine, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900, CEP: 14049-900 Ribeirão Preto, SP, Brazil. Electronic address: lfranco@fmrp.usp.br.
authors.forename: L J
authors.initials: LJ
authors.lastname: Franco
authors.affiliation: Department of Social Medicine, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900, CEP: 14049-900 Ribeirão Preto, SP, Brazil.
authors.forename: A L
authors.initials: AL
authors.lastname: Dal Fabbro
authors.affiliation: Department of Social Medicine, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900, CEP: 14049-900 Ribeirão Preto, SP, Brazil.
authors.forename: E Z
authors.initials: EZ
authors.lastname: Martinez
authors.affiliation: Department of Social Medicine, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900, CEP: 14049-900 Ribeirão Preto, SP, Brazil.
authors.forename: D S
authors.initials: DS
authors.lastname: Sartorelli
authors.affiliation: Department of Social Medicine, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900, CEP: 14049-900 Ribeirão Preto, SP, Brazil.
authors.forename: A S
authors.initials: AS
authors.lastname: Silva
authors.affiliation: Department of Social Medicine, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900, CEP: 14049-900 Ribeirão Preto, SP, Brazil.
authors.forename: L P
authors.initials: LP
authors.lastname: Soares
authors.affiliation: Division of Endocrinology, Escola Paulista de Medicina, Federal University of São Paulo. Rua Pedro de Toledo, 781-12 floor, CEP: 04039-001 São Paulo, SP, Brazil.
authors.forename: L F
authors.initials: LF
authors.lastname: Franco
authors.affiliation: Division of Endocrinology, Escola Paulista de Medicina, Federal University of São Paulo. Rua Pedro de Toledo, 781-12 floor, CEP: 04039-001 São Paulo, SP, Brazil.
authors.forename: P C
authors.initials: PC
authors.lastname: Kuhn
authors.affiliation: Division of Endocrinology, Escola Paulista de Medicina, Federal University of São Paulo. Rua Pedro de Toledo, 781-12 floor, CEP: 04039-001 São Paulo, SP, Brazil.
authors.forename: J P B
authors.initials: JP
authors.lastname: Vieira-Filho
authors.affiliation: Division of Endocrinology, Escola Paulista de Medicina, Federal University of São Paulo. Rua Pedro de Toledo, 781-12 floor, CEP: 04039-001 São Paulo, SP, Brazil.
authors.forename: R S
authors.initials: RS
authors.lastname: Moisés
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D001938:Brazil / Q000208:ethnology; D002196:Capillaries; D003920:Diabetes Mellitus / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology; D005260:Female; D005947:Glucose; D018149:Glucose Intolerance / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D007199:Indians, South American; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology; D011237:Predictive Value of Tests; D012307:Risk Factors; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D005947:Glucose; D006442:Glycated Hemoglobin
keywords: Brazilian Indians; Diabetes mellitus; HbA1c; Impaired glucose tolerance