Cardiovascular disease (CVD) event risk in adults with hypertension and left ventricular hypertrophy (LVH) is the lowest at systolic and diastolic blood pressure (BP) less than 130 mm Hg and less than 80 mm Hg, respectively, according to research results published in the Journal of the American College of Cardiology.
According to the study researchers, LVH is “consistently under-represented” in landmark trials like the Systolic Blood Pressure Intervention Trial (SPRINT) and the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study.
In the current study, researchers used an anonymized nationwide health examination and claims database from South Korea to evaluate the association between on-treatment blood pressure and cardiovascular outcomes in adults with hypertension and LVH.
The researchers also collected clinical and biochemical measurements as well as questionnaire-based lifestyle information from the database. The primary exposure was on-treatment BP averaged from all available examinations through December 31, 2008.
The primary study outcome was a composite CVD event, defined as the first hospitalization for myocardial infarction (MI), stroke, or heart failure (HF), or CVD-related death through December 31, 2019. Secondary outcomes were MI, stroke, and HF hospitalizations.
Overall, more than 12 million adults aged between 40 and 79 years underwent routine health examinations that included electrocardiography (ECG) between 2004 and 2008. A total of 11,673,788 participants had complete covariable information available. Of this group, 160,774 had received treatment for hypertension for at least a year and had available ECG findings of LVH.
A total of 95,545 participants had LVH on baseline ECG (median age, 62 years; 63.6% men). Of these, 4.6%, 18.0%, 32.0%, and 45.4% had a systolic BP of less than 120 mm Hg, 120 to 129 mm Hg, 130 to 139 mm Hg, and greater than or equal to 140 mm Hg, respectively. A total of 2.4%, 21.1%, 48.8%, and 27.7% had a diastolic BP of lower than 70 mm Hg, 70 to 79 mm Hg, 80 to 89 mm Hg, and greater than or equal to 90 mm Hg, respectively.
Those in higher systolic BP groups were generally older, while those in higher diastolic BP groups were generally younger. Participants who had higher vs lower BP typically had lower household income and Charlson comorbidity index. They were also more likely to be on combination antihypertensive therapy but less likely to be on lipid-lowering therapies. They were more frequent drinkers, less frequent exercisers, and had higher body mass index (BMI), cholesterol, and fasting glucose levels.
Over a median follow-up period of 11.5 years, a total of 12,035 new CVD events were recorded, with 442, 1709, 3406, and 6478 occurring in each systolic BP group, respectively, and 353, 2519, 5577, and 3586 in each diastolic BP group, respectively.
Researchers used the 120 to 129 mm Hg systolic BP group as a reference group and found that multivariable-adjusted hazard ratios (HRs) were 1.31 in the greater than or equal to 140 mm Hg group, 1.08 in the 130 to 139 mm Hg group, and 103 in the less than 120 mm Hg group. Using the diastolic BP 70 to 79 mm Hg as a reference, multivariable adjusted HRs were 1.30, 1.06, and 1.08 in the greater than or equal to 90 mm Hg, 80 to 89 mm Hg, and less than 70 mm Hg groups, respectively.
Adjusted cumulative incidence of CVD event was highest in the systolic BP group with greater than or equal to 140 mm Hg, followed by the 130 to 139 mm Hg and both the 120 to 129 mm Hg and less than 120 mm Hg groups. Adjusted cumulative CVD incidence was similar by diastolic BP.
Results of restricted cubic spline analyses found that the CVD event risk was lowest in those with systolic BP less than 130 mm Hg, while the CVD event risk increased log-linearly with systolic BP greater than or equal to 130 mm Hg. Similarly, this risk was the lowest in those with diastolic BP less than 80 mm Hg and increased with diastolic BP greater than or equal to 80 mm Hg.
In terms of secondary outcomes, the associations of systolic BP with CVD risk were “generally consistent” across outcomes and greater than or equal to 130 mm Hg, with systolic BP less than 130 mm Hg not associated with additional reductions in risks for stroke or HF. In terms of diastolic BP and CVD risk, associations were also consistent across these outcomes at greater than or equal to 80 mm Hg. Diastolic BP less than 80 mm Hg was not associated with additional reductions in MI or stroke risk but was associated with an elevated HF risk.
When stratified by conditions like hypercholesterolemia, diabetes, or monotherapy vs combination therapy, the association of both systolic and diastolic BP with CVD risk was consistent across subgroups. When stratified by sex, however, associations diverged at systolic and diastolic BP of greater than or equal to 160 mm Hg or less than 80 mm Hg, respectively.
Study limitations included the retrospective, nonrandomized nature of the research, a need to validate the diagnostic accuracy of LVH, potential for false positive LVH diagnoses due to the high specificity of ECG criteria in Asian populations, and a lack of assessment of LVH persistence or regression over follow-up.
“In adults with hypertension and LVH, on-treatment BP showed a log-linear association with the risk of CVD events,” the researchers concluded. “Further randomized trials are warranted to establish optimal BP-lowering strategies for patients with hypertension and LVH.”
Lee H-H, Lee H, Cho SMJ, Kim D-W, Park S, Kim HC. On-treatment blood pressure and cardiovascular outcomes in adults with hypertension and left ventricular hypertrophy. J Am Coll Cardiol. Published online October 2021. doi:10.1016/j.jacc.2021.08.015