Abstract
BACKGROUND: An intense increase in pre-diabetes has taken place among the worldwide population each year. The purpose of this study was to assess the diagnostic validity of the American Diabetes Association (ADA) screening questionnaire for identifying pre-diabetes in the Iranian rural population. METHODS: This study was conducted in Ahar County, East Azarbaijan, Iran. The participants (n = 440) were randomly recruited via trained community health care workers. The ADA questionnaire including six items (age, gender, having family members with diabetes, obesity, hypertension, and physical activity) is the screening tool used to identify people at high risk for developing type 2 diabetes. The World Health Organization (WHO) forward/backward translation protocol was used for translating the assessment tool. The diagnosis of pre-diabetes was defined based on the fasting blood glucose (FBG, as a gold standard) cut-points of 100 mg/dl to 125 mg/dl. We assessed the criterion validity and diagnosis characteristics of the ADA questionnaire in the diagnosis of pre-diabetes using the measures of sensitivity, specificity, and receiver operating characteristics (ROC) curves. In addition, the optimal cut-point of the ADA questionnaire for the diagnosis of pre-diabetes was computed using Youden's index. RESULTS: A total of 440 adults ages 30-65 years (Mage = 48.8 years, SDage = 11.2 years) were included in the study. Around half of the participants were women (50%), illiterate (51.4%), and married (85.2). In the pre-diabetes diagnosis scale, the present cut-point yielded a sensitivity of 98.7 (95% CI:96.6-99.6), specificity of 53.1 (95% CI: 44.6-61.5), positive predictive value (PPV) of 81.4 (95% CI:77-85.3), positive predictive value (NPV) of 95.0 (95% CI:87.7-98.6), and accuracy of 83.9 (95% CI:81.4-89.2) with an area under curve (AUC) of 0.84 (95% CI: 0.80 - 0.89). CONCLUSIONS: The Persian version of the ADA questionnaire had good sensitivity and fair specificity for pre-diabetes diagnosis among rural adults at high risk for developing type 2 diabetes. The study provided evidence for the ADA questionnaire as a valid and reliable tool for identifying pre-diabetes in a rural area. Identifying rural residents in the early stage of developing diabetes with a simple and accurate instrument without the need for a FBG test contributes to controlling the disease in areas with limited access to health services. TRIAL REGISTRATION: The study is not a trial; the registration number is not applicable.