Validation of the self-reported diagnosis of diabetes mellitus, hypercholesterolemia, and hypertension in Iran; STEPS 2016.

Purpose: As a part of STEPwise approach to risk factor Surveillance (STEPS) study, our aim was to evaluate the validity of the self-reported diagnosis of diabetes (DM), hypertension (HTN), and hypercholesterolemia (Hyper-Chol) in the Iranian population. Methods: Using systematic proportional to size cluster sampling, 27,232 participants were included in our study. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) to assess the validity of self-reported diagnoses. Furthermore, logistic regression was employed to examine the relationship between the validity of self-reported diagnoses and sociodemographic and lifestyle factors. All analyses were performed using STATA version 14. Results: The PPV for self-report of DM, HTN, and Hyper-Chol were estimated to be 69%, 74% and 80%, and NPV measured up to 95%, 84%, and 50%, respectively. Positive/negative self-reports were more accurate among older (younger) individuals. Age had a negative correlation with the validity of self-reported Hyper-Chol but a positive correlation with the validity of self-reported DM and hypertension HTN. Additionally, an increase in BMI was associated with an increase/decrease in PPV and a decrease/increase in NPV across all diseases. Conclusion: Self-report studies hold value in situations where direct in-person interaction is not feasible, either due to prohibitive costs or restrictions imposed by infectious diseases (COVID-19). Self-report surveys are valuable tools in studying the epidemiology of diseases; however, the type of the disease, the study purpose, either finding sick people or healthy people, the age subgroups, and socioeconomic status should be taken into consideration.