Validation of a screening tool for identifying Brazilians with impaired glucose tolerance

Abstract

This study was designed to validate a self-assessment tool for identifying Brazilians with Impaired Glucose Tolerance (IGT). The Finnish Diabetes Risk Score (FINDRISC) was applied in 829 people aged over 40 years without previous diagnosis of diabetes between November 2009 and April 2010 at the Viçosa city, Minas Gerais, Brazil. We randomly selected 300 subjects in the initial survey, which received by post a letter of invitation to attend the laboratory for the collection of the blood sample to identify levels of glycated hemoglobin (A1C). Of these 300 subjects invited, 162 attended subjects, this being the final sample for the validation study. The risk score was evaluated through the Area Under the Curve (AUC) in a Receiver Operating Characteristics (ROC) curve. We assume a maximum error of 5 % and confidence interval 95 %. The prevalence of IGT and diabetes according to the A1C test were 21.6 % and 8.6 % respectively. The Diabetes Risk Score value varied from 1 to 25. The AUC by considering all values of A1C ≥ 6.0 % was 0.69 (95 % CI 0.61–0.76). The score value ≥ 9 had sensitivity of 75.51 %, specificity of 49.56 %, Positive Predictive Value (PPV) of 39.4 % and Negative Predictive Value (NPV) of 82.4 %. The FINDRISC is a suitable tool to identify Brazilians with IGT.