Screening for Type 2 Diabetes and Impaired Glucose Metabolism

Abstract

OBJECTIVE -To assess the Australian protocol for identifying undiagnosed type 2 diabetes and impaired glucose metabolism. RESEARCH DESIGN AND METHODS -TheAustralian screening protocol recommends a stepped approach to detecting undiagnosed type 2 diabetes based on assessment of risk status, measurement of fasting plasma glucose (FPG) in individuals at risk, and further testing according to FPG. The performance of and variations to this protocol were assessed in a population-based sample of 10,508 Australians.RESULTS -The protocol had a sensitivity of 79.9%, specificity of 79.9%, and a positive predictive value (PPV) of 13.7% for detecting undiagnosed type 2 diabetes and sensitivity of 51.9% and specificity of 86.7% for detecting impaired glucose tolerance (IGT) or impaired fasting glucose (IFG). To achieve these diagnostic rates, 20.7% of the Australian adult population would require an oral glucose tolerance test (OGTT). Increasing the FPG cut point to 6.1 mmol/l (110 mg/dl) or using HbA 1c instead of FPG to determine the need for an OGTT in people with risk factors reduced sensitivity, increased specificity and PPV, and reduced the proportion requiring an OGTT. However, each of these protocol variations substantially reduced the detection of IGT or IFG.CONCLUSIONS -The Australian screening protocol identified one new case of diabetes for every 32 people screened, with 4 of 10 people screened requiring FPG measurement and 1 in 5 requiring an OGTT. In addition, 1 in 11 people screened had IGT or IFG. Including HbA 1c measurement substantially reduced both the number requiring an OGTT and the detection of IGT or IFG. Diabetes Care 27:367-371, 2004T ype 2 diabetes is a common and serious condition that is associated with reduced life expectancy and considerable morbidity. It may remain undetected for a number of years, and, consequently, a significant proportion of people with newly diagnosed type 2 diabetes has established complications at the time of diagnosis (1,2).The role of early detection of undiagnosed type 2 diabetes in asymptomatic individuals as a strategy to reduce the personal, public, and economic cost of type 2 diabetes has been extensively reviewed (3). Although there is some circumstantial evidence that earlier detection is associated with improved outcomes (4), definitive evidence of benefit is lacking. Despite this, early detection of type 2 diabetes continues to be recommended by a number of organizations (5,6).In Australia, the National Health and Medical Research Council has recently endorsed a national evidence-based guideline for case detection and diagnosis of type 2 diabetes (7). This guideline was developed through an extensive and systematic review of the literature. It recommends a stepped approach to the diagnosis of people with previously undiagnosed type 2 diabetes based on assessment of an individual's risk status, measurement of fasting plasma glucose (FPG) in individuals at risk, and further testing according to the FPG result (Fig. 1).Since the release of the findings of the Fin...

Data-analytically derived flexible HbA1c thresholds for type 2 diabetes mellitus diagnostic

“…So, the selector set includes: the T2DM, CVD and HT statuses, fasting glucose, age, waist-circumference-to-height ratio (WCHR), SBP lying, diabetic phenotype, joint cardio-vascular and joint cardio-neuropathic facts, graded heart function on results of ECG, combined causes of high BP, and gender. Indeed, the Australian T2DM screening protocol identifies following risk factors: [4] • People aged 55+ years;…”

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Assessing the cost-effectiveness of drug and lifestyle intervention following opportunistic screening for pre-diabetes in primary care

“…First, screening targeted at pre-diabetes will also identify some undiagnosed cases of diabetes. The AusDiab Study in Australia found that up to half of all people with diabetes were undiagnosed, whereas in the USA the National Health and Nutrition Examination Survey in 2005/06 reported that 40% of diabetes was [13,31]. Increased case finding would increase diabetes treatment costs, but would also lead to health benefits.…”

“…These guidelines were applied to the population in the AusDiab study and the rate of identification of people with pre-diabetes was calculated [13]. Inclusion criteria of the opportunistic screening programme included: (1) age >55 years; or (2) age >45 plus high BMI, family history of type 2 diabetes or hypertension; or (3) people from 'high-risk' groups (e.g.…”

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