The effect of varying the screening interval on false positives and duration of undiagnosed disease in a screening programme for type 2 diabetes

Abstract

Objectives-The aims of this study were to quantify the proportion of people diagnosed as having type 2 diabetes by standard 75 g oral glucose tolerance test, in a hypothetical screening programme, who would actually be false positives (false positive percentage), and the eVect on the false positive percentage of varying the time between repeat screens. We also calculated the duration in person years of exposure to undiagnosed disease in the population for each screening interval. Setting-Ely, Cambridgeshire, UK. Methods-We used the glucose tolerance data from 965 participants of the Ely Diabetes Project, who were tested 4.5 years apart, to calculate the population's between and within person variance for 2 hour plasma glucose, and constructed a probability matrix of observed v true glucose tolerance categories. The progression of the population between glucose tolerance categories was modelled assuming exponential times to progression. Results-After one year, 47.5% of test positives were disease free: almost half of those labelled with diabetes would not have the disease. For a 5 year interval, the false positive percentage was 27.6%, but the population would have been exposed to undiagnosed diabetes for 144 person years. Conclusions-Screening can be associated with both benefit and harm; the balance is dependent on characteristics of the disease and the screening programme. This study has quantified the trade oV between exposure to undiagnosed diabetes and false positive results to inform the debate about screening for type 2 diabetes. (J Med Screen 2000;7:91-96)

DISTq: An Iterative Analysis of Glucose Data for Low-Cost, Real-Time and Accurate Estimation of Insulin Sensitivity

“…This result is in contrast to a number of studies, which show relatively low repeatability in terms of re-classifying NGT, IGT and T2DM subjects (50-65% repetition) [7,10,34]. In contrast, Fig.…”

New criteria for impaired fasting glucose and screening for diabetes in cystic fibrosis: Fig. 1—

“…By definition, it needs at least two separate measures of glycaemic disturbance on separate days before the clinical diagnosis of CFRD can be made in this group of patients mainly displaying no acute symptoms of diabetes [10,13]. In a non-CF population screened by OGTT for type-2 diabetes 1 yr after the initial diabetic OGTT, a second OGTT returned to nondiabetic in 47% of the subjects [14]. In a CF population with an annual OGTT screening programme, only 10 out of 15 patients who were diabetic in the annual OGTT were also diabetic in a repeated OGTT [15].…”

DISTq: Low-cost, accurate and real-time estimation of insulin sensitivity

“…(Ferrannini et al 2005) found a R=0.74 correlation between the 2-hour oral-glucose tolerance test (OGTT) and the clamp which is comparable to our in silico correlation of R=0.81. However, the reproducibility of the OGTT has been called into question by a number of researchers who found NGT, IGT and T2DM re-classification rates of only 50-65% (Ko et al 1998;Levy et al 1999;Park et al 2000).…”