A simplified Indian Diabetes Risk Score for screening for undiagnosed diabetic subjects

The aim of this study was to develop and validate a simplified Indian Diabetes Risk Score for detecting undiagnosed diabetes in India.

The risk score was derived from the Chennai Urban Rural Epidemiology Study (CURES), an ongoing epidemiological study on a representative population of Chennai. Phase 1 of CURES recruited 26,001 individuals, of whom every tenth subject was requested to participate in Phase 3 for screening for diabetes using World Health Organization (WHO) 2 hour venous plasma glucose criteria [i.e. > or = 200 mg/dl]. The response rate was 90.4% (2350/2600). The Indian Diabetes Risk Score [IDRS] was developed based on results of multiple logistic regression analysis. Internal validation was performed on the same data.

IDRS used four risk factors: age, abdominal obesity, family history of diabetes and physical activity. Beta co-efficients were derived based on a multiple logistic regression analysis using undiagnosed diabetes as the dependent variable. The beta co-efficients were modified so as to obtain a maximum possible score of 100. Receiver Operating Characteristic [ROC] curves were constructed to identify the optimum value of IDRS for detecting diabetes by WHO consulting group criteria. Area under the curve for ROC was 0.698 (95% confidence interval (CI): 0.663-0.733). An IDRS value > or = 60 had the optimum sensitivity (72.5%) and specificity (60.1%) for determining undiagnosed diabetes with a positive predictive value of 17.0%, negative predictive value of 95.1%, and accuracy of 61.3%.

This simplified Indian Diabetes Risk Score is useful for identifying undiagnosed diabetic subjects in India and could make screening programmes more cost effective.