Cardiovascular events according to blood pressure thresholds recommended by ACC/AHA

The latest guidelines from ACC/AHA define hypertension at systolic blood pressure (SBP) 130-139 mmHg or diastolic blood pressure (DBP) 80-89 mmHg in contrast to guidelines from ESC/ESH defining hypertension at SBP ≥ 140 mmHg or DBP ≥ 90 mmHg. The aim was to determine whether the ACC/AHA definition of hypertension identifies persons at elevated risk for future cardiovascular outcome.

In a Danish prospective cardiovascular study, 19,721 white men and women aged 20-98 years were examined up to five occasions between 1976 and 2015. The population was followed until December 2018. The ACC/AHA definition of the BP levels were applied: Normal: SBP <120 mmHg and DBP <80 mmHg, Elevated: SBP 120-129 mmHg and DBP <80 mmHg, Stage 1: SBP 130-139 mmHg or DBP 80-89 mmHg, Stage 2: SBP ≥140 mmHg or DBP ≥90 mmHg. Absolute 10-year risk was calculated taking repeated examinations, covariates, and competing risk into account.

For all outcomes, the 10-year risk in stage 1 hypertension did not differ significantly from risk in subjects with normal BP: The 10-year risk of cardiovascular events in stage 1 hypertension was 14.1% [95% CI 13.2;15.0] and did not differ significantly from the risk in normal BP at 12.8% [95% CI 11.1;14.5] (p = 0.19). The risk was highest in stage 2 hypertension 19.4% [95% CI 18.9;20.0] and differed significantly from normal BP, elevated BP, and stage 1 hypertension (p < 0.001). The 10-year risk of cardiovascular death was 6.6% [95% CI 5.9;7.4] in stage 1 hypertension and did not differ significantly from the risk in normal BP at 5.7% [95% CI 4.1;7.3] (p = 0.33).

Stage 1 hypertension as defined by the ACC/AHA guidelines has the same risk for future cardiovascular events as normal BP. In contrast, the definition of hypertension as suggested by ESC/ESH identifies patients with elevated risk of cardiovascular events.

Until 2017, there was worldwide agreement on defining hypertension at systolic blood pressure (SBP) ≥ 140 mmHg or diastolic blood pressure (DBP) ≥ 90 mmHg.

In 2017, the American Cardiology Societies (ACC and AHA) lowered the threshold for defining hypertension at SBP 130-139 mmHg or DBP 80-89 mmHg.

Lowering the threshold might make healthy persons sick if the thresholds do not identify persons at high risk.

Unnecessary medical treatment is associated with high economic cost for the health care systems.

We wanted to explore whether applying the American BP definition in a Scandinavian population identified persons with elevated risk for cardiovascular disease.

As part of the Copenhagen City Heart study, 19,721 men and women aged 20-98 years were followed from 1976.

They went through up to five examinations between 1976 and 2018 including BP measurements.

We applied the American BP thresholds and followed the persons until death or 2018.

In Denmark all citizens have a unique identification number which is linked to all health care contacts and administrative registers.

We used advanced statistical methods and linked the BP measurements with the data for cardiovascular disease and death date from the Danish registries for each person.

The results showed that the American definition of hypertension has same risk for future cardiovascular disease as the definition of normal BP.

This means that healthy persons will be diagnosed with hypertension if the US guidelines were applied in Denmark.