The impact of low diastolic blood pressure on 30-day mortality of patients with acute myocardial infarction

Background It is known that low diastolic blood pressure (DBP) is associated with long-term cardiovascular events after acute myocardial infarction (AMI). However, the impact of low diastolic blood pressure on short-term outcome has not yet been well investigated. Methods and results We included 15,208 patients who were hospitalized for AMI and registered in the Tokyo CCU network registry between 2013 and 2016. Thirty-day in-hospital mortality rate was 4.8% (728/15,208). To assess the relationship between DBP at the time of admission and 30-day mortality non-linearly, spline regression model was applied with the stratification of the cohort according to tercile of systolic blood pressure (SBP, low:≤122 mmHg, intermediate:123–148 mmHg, high:≥149 mmHg) and J-curve phenomenon was observed in the low and high SBP groups. In multivariate logistic regression analysis, adjusted odds ratio of the lowest quintile of DBP (≤64 mmHg) was 1.65 (95% CI:1.02–2.66) in low SBP group and 4.55 (95% CI:1.72–12.00) in high SBP group. Conclusion Low DBP was associated with increased 30-day in-hospital mortality rate after AMI even in patients with high SBP.