Distribution of cardiovascular disease risk in adults aged 40 to 79 years with diagnosed hypertension but not on medications: findings from nationwide cross-sectional studies

Background Hypertension is the most important modifiable risk factor for cardiovascular disease (CVD). Many people with diagnosed hypertension are not receiving drug treatment, partly because they perceive their CVD risk as low. However, the distribution of CVD risk among these people remained largely unknown. Purpose To depict the risk of future CVD event, either first or recurrent, among people with diagnosed hypertension but not on antihypertensive drug treatment. Methods Participants aged 40-79 years who reported doctor-diagnosed hypertension but not on medications were identified from National Health and Nutrition Examination Surveys 1999 to 2018. Among them, the participants with known CVD, and those without known CVD but had complete data for estimating their 10-year predicted CVD risk, were included in the study. The 10-year predicted CVD risk was calculated using Pooled Cohort Equations as recommended in the 2019 American College of Cardiology/American Heart Association guideline on the primary prevention of CVD. The participants were categorised into 1) high risk if having known CVD, or a 10-year predicted CVD risk ≥10%; 2) low risk if having a 10-year predicted CVD risk <10%. The proportion of each risk group was calculated with the mobile examination center sample weights incorporated to account for the potential oversampling and non-response. The differences between subgroups in the distribution of CVD risk were assessed using Chi-squared test. Results Of the 2563 participants included, 1119 had known major CVD (n=396, 15.45%) or a 10-year predicted CVD risk ≥10% (n=723, 28.21%), corresponding to a weighted proportion of 35.75% (95% confidence interval: 32.99 to 38.50%), while the other participants had a low 10-year predicted CVD risk (weighted proportion: 64.25%, 61.50 to 67.01%). The proportions of high-risk participants were much higher in the elderly (71.63% for 60-79 years) and males (45.37%) than in others (both P<0.001). These patterns were consistent across ten survey cycles from 1999 to 2018. Conclusions One third of the US adults aged 40-79 years with diagnosed hypertension but not on medications had known CVD or a 10-year predicted CVD risk ≥10%, corresponding to over 3 million individuals. This proportion was little changed over the past two decades, highlighting the need for improvement in the management of CVD and its risk factors.