A Danish Diabetes Risk Score for Targeted Screening The Inter99 study CHARLOTTE GL ¨ UMER, MD 1,2 BENDIX CARSTENSEN, MSC 1 ANNELLI SANDBÆK, MD, PHD 3 TORSTEN LAURITZEN, MD, DMSC 3 TORBEN JØRGENSEN, MD, DMSC 2 KNUT BORCH-JOHNSEN, MD, DMSC 1 OBJECTIVE — To develop a simple self-administered questionnaire identifying individuals with undiagnosed diabetes with a sensitivity of 75% and minimizing the high-risk group needing subsequent testing. RESEARCH DESIGN AND METHODS — A population-based sample (Inter99 study) of 6,784 individuals aged 30 – 60 years completed a questionnaire on diabetes-related symptoms and risk factors. The participants underwent an oral glucose tolerance test. The risk score was derived from the first half and validated on the second half of the study population. External validation was performed based on the Danish Anglo-Danish-Dutch Study of Intensive Treat- ment in People with Screen Detected Diabetes in Primary Care (ADDITION) pilot study. The risk score was developed by stepwise backward multiple logistic regression. RESULTS — The final risk score included age, sex, BMI, known hypertension, physical ac- tivity at leisure time, and family history of diabetes, items independently and significantly (P  0.05) associated with the presence of previously undiagnosed diabetes. The area under the receiver operating curve was 0.804 (95% CI 0.765– 0.838) for the first half of the Inter99 population, 0.761 (0.720 – 0.803) for the second half of the Inter99 population, and 0.803 (0.721– 0.876) for the ADDITION pilot study. The sensitivity, specificity, and percentage that needed subsequent testing were 76, 72, and 29%, respectively. The false-negative individuals in the risk score had a lower absolute risk of ischemic heart disease compared with the true-positive individuals (11.3 vs. 20.4%; P  0.0001). CONCLUSIONS — We developed a questionnaire to be used in a stepwise screening strat- egy for type 2 diabetes, decreasing the numbers of subsequent tests and thereby possibly min- imizing the economical and personal costs of the screening strategy. Diabetes Care 27:727–733, 2004 D iabetes increases rapidly worldwide (1). In the U.S., the annual increase is currently 8.2%, probably due to the explosive increase in obesity over the last decade (2,3). In Denmark, the preva- lence of diabetes by age 60 years has in- creased by 58% in men and by 21% in women over a period of 20 years, mainly due to increased BMI (4). In an ongoing Danish intervention study, the crude prevalence of diabetes was 6.3, and 65% of the individuals with diabetes were un- aware of the disease (5), as was also found in previous studies (6,7). The age at onset of type 2 diabetes seems to decrease. In Denmark, type 2 diabetes is also diag- nosed in young adults (5), and in the U.S., type 2 diabetes is frequently seen in young adults (8). Studies have shown that 30 –50% of individuals with newly diag- nosed type 2 diabetes have one or more microvascular or macrovascular compli- cations at the time of diagnosis (6). Indi- viduals with previously undiagnosed diabetes have an unfavorable cardiovas- cular risk profile compared with glucose- tolerant individuals, indicating a higher risk for cardiovascular disease (9 –12). The American Diabetes Association (ADA) recommends regular screening for type 2 diabetes: patients should be screened at 3-year intervals beginning at age 45 years (13). In Denmark, regular screening is not recommended. Before implementation of screening, different uncertainties should be dissolved, includ- ing who should be screened, whether a high-risk group be identified, minimizing the need for subsequent testing, and whether screening is feasible. The aim of the present study is to de- velop a simple risk score based on a self- administered questionnaire, which can identify at least 75% of individuals with diabetes and reduce the number of subse- quent blood tests to 25%, and secondly, to evaluate the cardiovascular risk profile in individuals who are detected by the risk score compared with individuals who are missed (false negative) by the risk score. RESEARCH DESIGN AND METHODS — Based on a large popu- lation-based survey (Inter99) including 13,000 individuals (5), we subdivided the study population into two groups. The screening algorithm was developed based on the first half and validated in the sec- ●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●● From the 1 Steno Diabetes Centre, Gentofte, Denmark; the 2 Research Centre for Prevention and Health, Copenhagen County, Glostrup University Hospital, Glostrup, Denmark; and the 3 University of Århus, Department of General Practice, Århus, Denmark. Address correspondence and reprint requests to Charlotte Glu ¨ mer, MD, Steno Diabetes Centre, Niels Steensensvej 2, 2820 Gentofte, Denmark. E-mail: chgl@steno.dk. Received for publication 14 May 2003 and accepted in revised form 18 November 2003. The Steno Diabetes Centre is a hospital owned by Novo Nordisk but provides service for the National Health Care system in Denmark. K.B.-J., B.C., and C.G. hold individual shares in Novo Nordisk. T.L. and A.S. receive funds from Novo Nordisk and Astra Zeneca for screening and intensive treatment of type 2 diabetes. Abbreviations: ADDITION, Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen Detected Diabetes in Primary Care; AUC, area under the curve; IGT, impaired glucose tolerance; IHD, ischemic heart disease; LADA, latent autoimmune diabetes in adulthood; OGTT, oral glucose tolerance test; ROC, receiver operating characteristic; SDM, screen-detected diabetes. © 2004 by the American Diabetes Association. Emerging Treatments and Technologies O R I G I N A L A R T I C L E DIABETES CARE, VOLUME 27, NUMBER 3, MARCH 2004 727