Personal characteristics effects on validation of self-reported type 2 diabetes from a cross-sectional survey among Chinese adults.

The objective was to evaluate the effects of personal characteristics on the validation of self-reported type 2 diabetes among Chinese adults in urban Shanghai. During 2015 to 2016, 4,322 participants were recruited in this validation study. We considered the criteria of diabetes verification to use the laboratory assays of fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), or taking diabetic medication. When taking diabetic medication or FPG≥7.0mmol/L was as identified diabetes, the measurements of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and Kappa value of self-reported diabetes were 72.0%, 99.2%, 95.1%, 93.9%, and 0.78, respectively. If an additional HbA1c test was used for 708 subjects (aged<65 years), slightly lower values of sensitivity, NPV and Kappa were observed. More potential diabetes cases were found if compared to only using FPG. Subjects with the characteristics of female, older, or family history of diabetes had sensitivity over 75% and over 0.8 of excellent Kappa, while the sensitivity and Kappa of opposite groups had poorer values. Specificity, PPV and NPV were similar in different characteristics populations. The prevalence of type 2 diabetes was 19.3% in the study (14.1% diagnosed diabetes, 5.2% undiagnosed diabetes). About 26.2% of subjects were pre-diabetes. Additional HbA1c test indicated an increased prevalence of undiagnosed and pre-diabetes. Findings support self-reported diabetes is sufficiently valid to be used in large-scale, population-based epidemiologic studies. Participants with different characteristics may have different indicators in terms of validation such as age, gender, and family history of diabetes in first-relatives.