Validating self-report of diabetes and hypertension use by participants in the pilot phase of Azar cohort study: comparison with paraclinic indicators، medical history and medical examination

Abstract

Objective: Usually self-reported data is used to estimate the prevalence of health conditions and the use of preventive health services in the population, but usually the validity of such data is questionable. The purpose of this study was to validate self-reported diabetes and hypertension in a population of 35 years and over in Khameneh in the pilot phase of the cohort Azar. Methods: 1038 people over 35 years old participated in the study. Participants were asked, Has your doctor ever told you to have diabetes or high blood pressure? All subjects were evolated for anthropometric indices, socio-economic status, lifestyle, history of diseases and medicine use, physical activity, and did paraclinical routine tests. Evaluation validity of self-reported hypertension and diabetes were compared through paraclinical examinations, clinical examinations and medical records, and sensitivity, specificity, positive predictive value, negative predictive value, and correctness ratio were calculated for this purpose. The validity of self-reported hypertension and diabetes was measured by sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio. Results: The sensitivity of self-reported diabetes and hypertension were respectively 58.4% (95%CI: 43.5-65.5) and (85%) (95%CI: 79.3% -89.5%).The specificity96.9% (95%CI:94.5-97.3) was calculated for hypertension and 99.7% (95%CI:98.5-100) for diabetes . Positive and negative predictive values was calculated for diabetes 90.4(95%CI: 85.5-95.5)‚ 91.9(95%CI:83.9-93.6) and hypertension 84.1(95%CI:78.4-88.8)‚96.3 (95%CI:94.7-97.4). The medium agreement was obtained between self-reported diabetes with medicine use and paraclinical tests 0.66 (95%CI: 0.61-0.79) and Kappa was excellent for self-reported hypertension with medicine use and clinical examinations 0.8(95%CI:0.76-0.85). Conclusion: The validity of self-report was high in hypertension and moderate in diabetes. Age‚ sex‚ BMI and WHR were the main factors influencing inaccuracy self-report of diabetes. Age and comorbidity were identified as factors influencing on the inaccuracy of self-report hypertension.