Reproducibility of the diagnosis of diabetes over a 30-month follow-up -: The Paris Prospective Study

OBJECTIVE - To describe the change in diabetic status over 30 months. RESEARCH DESIGN AND METHODS - Cohort study of 5,400 Caucasian men from the Paris Prospective Study, aged 44-55 years, who were not known as having diabetes at baseline. Oral glucose tolerance tests were performed at baseline and after 30 months. RESULTS - At baseline, diabetes was diagnosed in 2.9% of the men by fasting plasma glucose (FPG) greater than or equal to7.0 mmol/l and in 0.9% by isolated postchallenge hyperglycemia (IPH) (FPG <7.0 mmol/l and 2-h plasma glucose concentration greater than or equal to 11.1 mmol/l), i.e., one in four of all men with newly diagnosed diabetes. Thirty months later, 42% of the men with diabetes diagnosed by FPG reverted to nondiabetic status, compared with 72% of those with diabetes diagnosed by IPH (P < 0.0001). For the men with diabetes diagnosed by FPG at baseline, diabetes had been diagnosed by a physician at 30 months in 11.5%,in contrast to only 3.9% of those with diabetes diagnosed by IPH (P < 0.05). For the 51 men with diabetes diagnosed by IPH at baseline, those who reverted to nondiabetic status had a lower frequency of family history of diabetes (P < 0.1), a higher mean corpuscular volume (P < 0.08), and a significantly higher total cholesterol concentration (P < 0.006) at baseline in contrast, for the 156 men with diabetes diagnosed by FPG at baseline, the men who reverted to nondiabetic status and those who remained diabetic had similar characteristics. CONCLUSIONS - In this epidemiological study, diabetes diagnosed by one FPG concentration was more stable than diabetes diagnosed by one IPH; in clinical practice, the diagnosis of diabetes requires confirmation of the hyperglycemia.