Comparison of three methods for diabetes screening in a rural clinic in Honduras

Abstract

To evaluate two alternatives to the fasting plasma glucose (FPG) test for diabetes screening in Latin America. Eight hundred adults without diabetes were recruited in a primary care clinic in Honduras. An equation-based screening formula, incorporating a random capillary glucose test and other risk factors, was used for initial screening. All patients with a screening-based probability of diabetes > 20%, plus one-fifth of those with a probability < 20%, were asked to return for FPG and point-of-care hemoglobin A1c (POC-A1c) tests. An FPG > 126 milligrams per deciliter and a POC-A1c > 6.5% were used as gold standards to assess the performance of the screening equation. The association between the POC-A1c and the FPG tests was examined as were patient factors associated with failure to return for follow-up and variation in diabetes risk across subgroups. The screening equation had excellent test characteristics compared with FPG and POC-A1c. Using the FPG gold standard, the POC-A1c had a sensitivity of 77.8% and a specificity of 84.9%. With an A1c cutoff of 7%, POC-A1c specificity increased to 96.2%. Thirty-four percent of patients asked to return for follow-up testing failed to do so. Those who failed to return were more likely to be men and to have hypertension. Both the screening equation and POC-A1c are reasonable alternatives to an FPG test for identifying patients with diabetes. Given the barriers to currently recommended screening procedures, these options could have important public health benefits in Latin America.