Epidemiology of Resistant Hypertension in Canada

BACKGROUND: Resistant hypertension is associated with cardiovascular morbidity and mortality. The objective of this study was to estimate the prevalence of apparent treatment-resistant hypertension in Canadian adults and examine the characteristics of those affected. METHODS: A nationally representative cross-sectional study was conducted with the use of Canadian Health Measures Survey (2007-2017) data. The frequency of respondents with uncontrolled blood pressure despite 3 or more antihypertensive medications of different drug classes (and at least 1 agent being a diuretic), or treatment with 4 or more agents regardless of blood pressure, was determined. RESULTS: A total of 245,700 people were identified to have apparent treatment-resistant hypertension, representing 5.3% (95% confidence interval [CI] 4.5%-6.2%) of adults treated for hypertension in Canada. Respondents who had uncontrolled blood pressure with 3 or more antihypertensive drugs were more likely women (55.8%, 95% CI 41.1%-70.4%), 70 years of age or older (45.3% 95% CI 32.8%-57.9%), and overweight or obese (84.2%, 95% CI 72.3%-96.1%). Respondents with apparent treatment-resistant hypertension also had a high likelihood of chronic kidney disease (36.0%, 95% CI 21.4%-50.6%), diabetes (35.2%, 95% CI 21.7%-48.7%), dyslipidemia (68.0%, 95% CI 55.2%-80.8%), and history of heart attack (9.9%, 95% CI 4.8%-15.1%) or stroke (7.1%, 95% CI 0-14.4%). CONCLUSIONS: Despite being prescribed at least 3 antihypertensive drugs, a considerable proportion of Canadians, especially women, have difficulty achieving blood pressure control, predisposing them to a higher risk of cardiovascular complications and death.