Validity and Concordance Between Self-Reported and Clinical Diagnosis of Hypertension Among Elderly Residents in Northeastern Brazil

BACKGROUND: Self-reported information has been used as an easy and quick method to estimate the prevalence of systemic hypertension in populations. However, verification of whether self-reports of the disease are consistent with clinical diagnosis is essential for proper use of this information. This study aimed to verify the validity and concordance between self-reported and clinical diagnosis of hypertension in the elderly population of a city in northeastern Brazil. METHODS: This was a cross-sectional and population-based study. The prevalence of diagnosed and self-reported hypertension and the validity and concordance between self-reported and clinical diagnosis and their distribution according to demographic and socioeconomic variables were assessed. The validity of self-reported hypertension was determined by sensitivity, specificity, and positive and negative predictive value. RESULTS: Overall, 795 elderly patients were evaluated (69.1% women). There was a high prevalence of hypertension among the elderly (diagnosed: 75.1%, 95% confidence interval (CI) = 71.1%-77.9%; self-reported: 59.7%, 95% CI = 56.3%-63.1%). For self-reported hypertension, sensitivity was substantial (77.1%), specificity was excellent (93.4%), positive predictive value was excellent (97.3%), and negative predictive value was moderate (57.2%). There was a moderate concordance between self-reported and clinical diagnosis of hypertension (kappa = 0.59; P < 0.001). CONCLUSIONS: Reasonable validity and moderate concordance of self-reported information on hypertension was observed, which reinforces the idea that this information can be used as strategy for detecting the disease prevalence in this population. However, because of nonachievement of excellence in the validity and reliability of the measured blood pressure, this information should be carefully considered for the strategic planning of health services.