Importance: The 2017 American College of Cardiology and American Heart Association (ACC/AHA) blood pressure (BP) guidelines redefined hypertension using a BP threshold of 130/80 mm Hg or greater and applied a treatment target of less than 130/80 mm Hg.
Objective: To evaluate the potential change in the diagnosis, treatment, and control of hypertension in a Canadian cohort of patients with hypertension attending primary care practices using the ACC/AHA guidelines.
Design, setting, and participants: This cross-sectional study used primary care practices across Canada electronic medical record data from the Canadian Primary Care Sentinel Surveillance Network, extracted as of June 30, 2015. Adults with at least 1 primary care encounter in the previous 2 years (July 1, 2013, to June 30, 2015) were included in the study. Those with current hypertension were identified using a validated definition consisting of diagnoses, billing codes, and/or antihypertensive medication from within the primary care electronic medical record. Data analysis was conducted from December 2017 to July 2018.
Main outcomes and measures: Proportion of individuals with a diagnosis of hypertension, prescribed antihypertensive medication, and meeting treatment BP targets.
Results: Of the 594 492 Canadian participants included in the study, 144 348 (24.2%) had hypertension (45.6% male; mean [SD] age, 65.5 [14.5] years). On applying the ACC/AHA guidelines, 252 279 individuals (42.4%) were considered hypertensive and half (51.0%; 95% CI, 50.8%-51.2%) were prescribed an antihypertensive medication. Individuals who were not previously considered to have hypertension but were reclassified as having elevated BP using the lower cutoff of 130/80 mm Hg or greater tended to be younger and were at lower cardiovascular risk. There was a shift toward more individuals requiring antihypertensive treatment, particularly in the lower-risk categories. The crude prevalence of hypertension increased from 13.3% to 32.0% in those aged 18 to 64 years, and of those aged 65 years and older, 16.6% more individuals were reclassified as having hypertension (from 55.2% to 71.8%). Only 12.3% of those who were considered at high risk were reclassified as hypertensive.
Conclusions and relevance: Adoption of the ACC/AHA BP guidelines would result in a near doubling in the prevalence of hypertension in Canada. The changes would largely affect individuals who are younger and at low to moderate cardiovascular risk.