A screening procedure detecting high-yield candidates for OGTT. The Women's Health in the Lund Area (WHILA) study: a population based study of middle-aged Swedish women

The objective was to evaluate a screening procedure for detecting high-yield candidates for an OGTT, in a population of middle-aged Swedish women. A two-step screening procedure was performed in 6917 subjects. Women with a positive screening outcome, i.e. increased non-fasting capillary blood glucose, serum triglycerides, BMI, WHR, blood pressure or a family history of diabetes, pharmacological treatment of hypertension or hyperlipidaemia at the primary screening underwent a 75-g OGTT. A control group of women with negative screening outcome (n = 221) also underwent an OGTT. In 2923 women with positive screening outcome, 517 (17.7%) had NFG/IGT (normal fasting venous blood glucose <5.6 mmol/l and 2h-glucose 6.7–9.9 mmol/l), 109 (3.7%) IFG/IGT (fasting 5.6–6.0 and 2h 6.7–9.9 mmol/l) and 223 (7.6%) diabetes (fasting 6.1 or 2h 10.0 mmol/l). These figures were three, five and four times higher, respectively, than in the control group with negative screening outcome (p < 0.001 for all); no differences were found for IFG/NGT (fasting 5.6–6.0 and normal 2h < 6.7 mmol/l) (4.6% vs. 7.2%). For predicting impaired glucose metabolism (IFG/NGT, NFG/IGT, IFG/IGT, diabetes), the screening instrument showed an estimated sensitivity of 70%, specificity of 55%, positive predictive value of 34% and negative predictive value of 85%, based on findings in the control sample. The odds ratio for NFG/IGT increased with the numbers of risk factors from 2.8 to 7.7, for IFG/IGT from 5.7 to 55.0 and for diabetes from 2.5 to 18.1. High B-glucose, WHR and BMI were the three most important factors associated with an increased risk for NFG/IGT, IFG/IGT and diabetes. In subjects with IFG/NGT, none of the screening variables was associated with an increased risk. In summary, the results show a population screening method focused on features of the metabolic syndrome that discloses high-yield candidates for OGTT. A high prevalence of unknown impaired glucose metabolism was found in middle-aged women with a positive screening profile.