Screening for type 2 diabetes--where are we now?

Reconsidering the age thresholds for type II diabetes screening in the U.S

BACKGROUND

Type II diabetes and its complications can sometimes be prevented, if identified and treated early. One fifth of diabetics in the U.S. remain undiagnosed. Commonly used screening guidelines are inconsistent.

PURPOSE

To examine the optimal age cut-point for opportunistic universal screening, compared to targeted screening, which is recommended by U.S. Preventive Services Task Force (USPSTF) and American Diabetes Association (ADA) guidelines.

METHODS

Cross-sectional analysis of a nationally representative sample from the National Health and Nutrition Examination Survey, 2007-2010. Number of people needed to screen (NNS) to obtain one positive test result was calculated for different guidelines. Sampling weights were applied to construct national estimates. The 2010 Medicare fee schedule was used for cost estimation. Analysis was conducted in January 2014.

RESULTS

NNS, under universal screening, drops sharply at age 35 years, from 80 (30-34-year-olds) to 31 (35-39-year-olds). Opportunistic universal screening of eligible people aged ≥35 years would yield an NNS of 15, translating to $66 per positive test. Among people aged 35-44 years (who are not recommended for universal screening by ADA), most (71%) were overweight or obese and all had at least one other ADA risk factor. Only 34% of individuals aged ≥35 years met USPSTF criteria. Strictly enforcing USPSTF guidelines would have resulted in a majority (61%) of potential positive test cases being missed (5,508,164 cases nationwide).

CONCLUSIONS

Opportunistic universal screening among individuals aged ≥35 years could greatly reduce the national prevalence of undiagnosed pre-diabetes or diabetes at relatively low cost.

Screening for type 2 diabetes. Lessons from the ADDITION-Europe study

AIMS

To describe and compare attendance rates and the proportions of people identified with Type 2 diabetes mellitus in people with previously unknown diabetes who participated in screening programmes undertaken in general practice in the UK, Denmark and the Netherlands as part of the ADDITION-Europe study.

METHODS

In Cambridge, routine computer data searches were conducted to identify individuals aged 40-69 years at high risk of Type 2 diabetes using the Cambridge Diabetes Risk Score. In Denmark, the Danish Diabetes Risk Score was mailed to individuals aged 40-69 years, or completed by patients visiting their general practitice. In the Netherlands, the Hoorn Symptom Risk Questionnaire was mailed to individuals aged 50-69 years. In these three centres, high-risk individuals were invited to attend subsequent steps in the screening programme, including random blood glucose, HbA(1c) , fasting blood glucose and/or oral glucose tolerance test. In Leicester, eligible people aged 40-69 years were invited directly for an oral glucose tolerance test. In all centres, Type 2 diabetes was defined according to World Health Organization 1999 diagnostic criteria.

RESULTS

Attendance rates ranged from 20.2% (oral glucose tolerance test in Leicester without pre-stratification) to 95.1% (random blood glucose in opportunistic screening in Denmark in high-risk people). The percentage of people with newly detected Type 2 diabetes from the target population ranged from 0.33% (Leicester) to 1.09% (the Netherlands).

CONCLUSIONS

Screening for Type 2 diabetes was acceptable and feasible, but relatively few participants were diagnosed in all participating centres. Different strategies may be required to increase initial attendance and ensure completion of screening programmes.