Likelihood of having isolated postchallenge hyperglycemia in an Iranian urban population

To identify subjects who would most likely benefit from oral glucose tolerance test (OGTT) for diagnosis of diabetes mellitus (DM), namely isolated postchallenge hyperglycemia (IPH) (i.e. FPG < 126 mg/dl and 2 h-PG ≥ 200 mg/dl), we evaluated data and results of OGTT of 9745 participants of Tehran Lipid and Glucose Study (TLGS), aged >20 years and without previously diagnosed DM.The overall prevalence of IPH was 3.1% (95% CI: 2.8–3.4%, n = 302). In the multivariate logistic regression analysis, the odds ratios (OR) for IPH were statistically significant for FPG ≥ 100 mg/dl (OR 9.5; 95% CI: 7.1–12.5), age ≥40 years (OR 2.6; 95% CI: 1.8–3.7), triglycerides ≥200 mg/dl (OR 2.1; 95% CI: 1.6–2.7), hypertension (OR 2.0; 95% CI: 1.5–2.6) and abnormal waist circumference (OR 1.9; 95% CI: 1.3–2.8). In subjects with FPG < 126 mg/dl, findings that best distinguished between IPH and non-diabetic subjects were FPG ≥ 100 mg/dl [positive likelihood ratio (LR(+)) = 5.2], FPG ≥ 100 mg/dl together with triglycerides ≥200 mg/dl [LR(+) = 9.7] and a combination of all the five factors [LR(+) = 12.9].This analysis showed that in Iranian urban subjects with FPG < 126 mg/dl, factors such as FPG ≥ 100 mg/dl, older age, hypertriglyceridemia, hypertension and abnormal waist circumference were the best predictors of presence of IPH; OGTT would hence be recommended for opportunistic screening of IPH in subjects with above mentioned characteristics.