The Performance of a Risk Score as a Screening Test for Undiagnosed Hyperglycemia in Ethnic Minority Groups

Abstract

OBJECTIVE -To assess the performance of the Cambridge Risk Score (CRS) to predict undiagnosed hyperglycemia in Caribbean and South Asian people living in the U.K. RESEARCH DESIGN AND METHODS -The CRS uses routinely available data from primary care records to identify people at high risk for undiagnosed type 2 diabetes. The sensitivity, specificity, and area under the receiver operator characteristic (ROC) curve for the CRS cut point of 0.199 were 77, 72, and 80% (95% CI 68 -91), respectively. The risk score was calculated for 248 Caribbean and 555 South Asian participants aged 40 -75 years in the 1999 Health Survey for England. Undiagnosed hyperglycemia was considered present if fasting plasma glucose was Ն7.0 mmol/l or HbA 1c was Ն6.5%. Sensitivity, specificity, and predictive values were calculated for various cut points of the risk score, and ROC curves were constructed.RESULTS -The area under the ROC curve was 67% (59 -76) and 72% (67-78) for Caribbeans and South Asians, respectively. The optimal cut point in Caribbean participants was 0.236, sensitivity was 63% (46 -77), and specificity was 63% (56 -69). In the South Asian population, the optimal cut point was and 0.127, sensitivity was 69% (60 -78), and specificity was 64% (60 -69).CONCLUSIONS -The CRS, using routinely available data, can be used in a strategy to detect undiagnosed hyperglycemia in Caribbean and South Asian populations. The existence of ethnic group-specific cut points must be further established in future studies. Diabetes Care 27:116 -122, 2004T he high prevalence of undiagnosed diabetes (1-3) and the demonstration of evidence of diabetic complications at the time of diagnosis (4) have led to recommendations for screening for type 2 diabetes by the American Diabetes Association (ADA) and Diabetes U.K.(5,6). One possible way of screening for type 2 diabetes is with simple risk scores based on data that are routinely available in primary care (7,8). Risk scores and questionnaires for type 2 diabetes have been developed and tested in mainly Caucasian populations (7-10), but it is uncertain whether these instruments could be used to identify undiagnosed diabetes in non-Caucasian populations as well. The ADA questionnaire is the only screening tool including a question about ethnicity (11). To our knowledge, no risk score for type 2 diabetes has been developed specifically for non-Caucasian populations. The demonstration of the validity of existing scores in specific ethnic groups or the development of ethnic-specific risk scores would be important because the prevalence of type 2 diabetes in individuals of African-Caribbean and South Asian origin is high, ranging from 14.6 to 17% in Caribbeans (12,13) and from 20 to 25.4% in South Asians (13-15); ϳ40% of cases are undiagnosed (16).We have previously developed and tested a risk score that uses routinely available data from primary care records to identify individuals at high risk for undiagnosed type 2 diabetes. In the U.K., virtually all individuals in the population are registered with a pr...

Age, BMI, and Race Are Less Important Than Random Plasma Glucose in Identifying Risk of Glucose Intolerance

“…AROCs ranged from 0.58 -0.80 with risk factor models in previous studies (7)(8)(9)(10)(11), comparable with or lower than RPG alone in the present study. However, we find that combination of risk factors and RPG improves AROC significantly (not shown).…”

Random Plasma Glucose in Serendipitous Screening for Glucose Intolerance: Screening for Impaired Glucose Tolerance Study 2

“…Questionnaires based on symptoms and risk factors have also been developed as inexpensive strategies to identify patients who need further evaluation. Although some questionnaires have been reported to provide AROC for diabetes~0.80, [36][37][38] comparable to that of screening with RPG, most provide 0.70-0.75, [39][40][41] and some that initially appeared promising had lower performance when applied to a separate population in the same city. 42 In the USA, it has been estimated that diabetes goes on for 10 years before clinical recognition, 43 and longer delay leads to higher glucose levels at the time of diagnosis.…”

Detection of impaired glucose regulation and/or type 2 diabetes mellitus, using primary care electronic data, in a multiethnic UK community setting

“…The Cambridge Risk score was designed to identify undiagnosed diabetes only and does not adjust for ethnicity [13]. Although not taken into account in the original score, a post hoc study using data from both Caribbean and South Asian populations showed that using alternative ethnic specific cut points could give acceptable levels of prediction for undiagnosed hyperglycaemia in these groups, but that further work needed to be carried out to refine these [23]. The QDScore predicts the 10 year risk of developing diabetes and includes similar variables to both the Cambridge Risk Score and the scores developed here, but with the addition of deprivation and cardiovascular disease (both of these were found not to improve the fit of models produced) [14].…”