The performance of a risk score as a screening test for undiagnosed hyperglycemia in ethnic minority groups: data from the 1999 health survey for England.

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 >/=7.0 mmol/l or HbA(1c) was >/=6.5%. 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.