Low on-treatment blood pressure and cardiovascular events in patients without elevated risk: a nationwide cohort study

Insufficient blood pressure control among patients with hypertension without elevated risk is a global concern, suggesting the need for treatment optimization. However, the potential harm of excessive blood pressure lowering among these patients is understudied. This study addressed this evidence gap by using nationally representative public health insurer database covering 30 million working-age population. Patients who were continuously using antihypertensive drugs with 10-year cardiovascular risk <10% were identified. They were categorized by on-treatment systolic and diastolic blood pressures. The primary outcome was a composite of myocardial infarction, stroke, heart failure hospitalization, and peripheral artery disease. Of 920,533 participants (mean age, 57.3 years; female, 48.3%; mean follow-up, 2.75 years), the adjusted hazard ratios for systolic blood pressure of <110, 110-119, 120-129 (reference), 130-139, 140-149, 150-159, and ≥160 mmHg were 1.05 (95% confidence interval: 0.99-1.12), 0.97 (0.93-1.02), 1 (reference), 1.05 (1.01-1.09), 1.15 (1.11-1.20), 1.30 (1.23-1.37), and 1.76 (1.66-1.86), respectively; and for diastolic blood pressure of <60, 60-69, 70-79 (reference), 80-89, 90-99, and ≥100 mmHg were 1.25 (1.14-1.38), 0.99 (0.95-1.04), 1 (reference), 1.00 (0.96-1.03), 1.13 (1.09-1.18), and 1.66 (1.58-1.76), respectively. Among low-risk patients with hypertension, diastolic blood pressure <60 mmHg was associated with increased cardiovascular events, while systolic blood pressure <110 mmHg was not. Compared to previous investigations in high-risk patients, the potential harm of excessive blood pressure lowering was less pronounced in low-risk patients with hypertension. The association between low on-treatment blood pressure and cardiovascular events has been understudied in low-risk patients with hypertension. In our study with nationally representative working-age adults from general population with hypertension without elevated risk, increased risk of cardiovascular events was observed in diastolic blood pressure of <60 mmHg, but not in systolic blood pressure of <110 mmHg. Those results contrasted with previous investigations in high-risk patients where the risk of low on-treatment blood pressure was more pronounced.