Abstract
Background
Diastolic blood pressure has a J-curve relation with coronary heart disease and death, but it is debating whether a J-curve association exists in general population. We aimed to assess the relation of blood pressure to mortality, and whether their association is interacted with presence of high coronary artery calcium (CAC).
Methods
The KOICA registry is a retrospective, multicenter observational study designed to investigate the effectiveness and prognostic value of CAC score for primary prevention of cardiovascular disease in asymptomatic Korean adults. The association between CAC score and blood pressure was assessed. Patients were divided into 2 groups according to the baseline CACS (> 300 and ≤ 300), and all-cause mortality was assessed.
Results
The study population composed 48903 subjects with a mean age of 54 ± 9. There were 425 (0.9%) deaths during follow-up. At baseline, SBP (systolic blood pressure) more than 110 mmHg and DBP (diastolic blood pressure) more than 80 mmHg was associated with increased risk for CACS > 300. In patients with baseline CACS ≤ 300, all-cause mortality was increased in patients with SBP of 110-119 mmHg (HR 1.47, p = 0.023), 130-139 mmHg (HR 1.72, p = 0.002) and ≥ 140 mmHg (HR 1.47, p = 0.042) compared to SBP of 120-129 mmHg, whereas DBP did not predict all-cause mortality. In contrast, SBP was not associated to all-cause mortality in patients with CACS > 300, whereas DBP < 60 mmHg (HR 3.53, p =0.018) and 70-79 mmHg (HR 2.21, p = 0.042) was associated with increased risk for all-cause mortality compared to DBP of 80-89 mmHg.
Conclusion
Low DBP was associated with increased risk for all-cause mortality in subjects with high CAC score, suggesting high-risk for coronary artery disease. However, this J-curve relation was not shown in the population with low CAC score.
Diastolic Blood Pressure and the J-Curve—Causal Effect or Confounding?
