Potential impact of a change in the diagnostic criteria for diabetes mellitus on the prevalence of abnormal glucose tolerance in a local community at risk of diabetes: impact of new diagnostic criteria for diabetes mellitus

AIMS: To compare the prevalence of diabetes and abnormal glucose metabolism using conventional and suggested new WHO and new ADA criteria in a group of people with symptoms of diabetes. METHODS: We examined retrospectively the results of 154 consecutive OGTTs in such patients performed using capillary whole blood. RESULTS: With the 1985 WHO criteria. Forty-four point eight per cent of subjects (69 subjects, with 95% confidence intervals, 37-52.6%) had diabetes, 47.8% (33 subjects, 36-59.6%) had a normal fasting glucose, 31.2% (48 subjects, 23.9-38.5%) had impaired glucose tolerance (IGT) and 76% (117 subjects, 69.3-82.7%) had abnormal glucose tolerance. Applying the ADA criteria (fasting capillary whole blood only), 33.1% (51 subjects, 25.7-40.5%) had diabetes (a 26% relative reduction) and 11% (17 subjects, 6.1-15.9%) IFG, with 44.1% (68 subjects, 36.3-51.9%) having abnormal glucose metabolism (a 42% relative reduction). If the proposed 1998 WHO criteria were used, the number with diabetes increase to 48% (74 subjects, 40.1-55.9%) a 7.2% increase on the old criteria. 27.9% (43 subjects, 20.8-35%) had IGT, so the number with some degree of abnormal glucose metabolism remains unchanged. Use of the ADA criteria, considering only the fasting glucose as suggested, will result in a significant reduction in the diagnosis of diabetes and those with abnormal glucose metabolism.