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Blood pressure and mortality among men with prior myocardial infarction. Multiple Risk Factor Intervention Trial
1Hypertension Division, Bowman Gray School of Medicine, Winston-Salem, NC 27157-1032, USA.
Insights
Blood pressure (BP) levels after myocardial infarction (MI) impact mortality risk. Early on, a J-shaped relation existed for older men, but after two years, higher BP, especially systolic BP (SBP), correlated with increased death from coronary heart disease (CHD) and all causes.
Area of Science:
- Cardiovascular Medicine
- Epidemiology
- Clinical Research
Background:
- Understanding the long-term impact of blood pressure on mortality post-myocardial infarction (MI) is critical for patient management.
- Previous research has established links between hypertension and cardiovascular events, but specific patterns following MI require further elucidation.
Purpose of the Study:
- To investigate the relationship between systolic blood pressure (SBP) and diastolic blood pressure (DBP) and mortality from coronary heart disease (CHD) and all causes in men with a history of MI.
- To analyze how this relationship evolves over a 16-year follow-up period.
Main Methods:
- A cohort of 5362 men aged 35-57 with prior MI, screened for the Multiple Risk Factor Intervention Trial (MRFIT) between 1973-1975, was followed for an average of 16 years.
- Survival data was analyzed, examining the association between baseline SBP and DBP levels and subsequent CHD and all-cause mortality, with attention to early (first 2 years) versus later follow-up periods.
Main Results:
- A J-shaped relationship between SBP/DBP and mortality was observed in older men during the first two years post-MI.
- After the initial two years, a positive, graded association emerged: higher SBP significantly increased the risk of both CHD and all-cause mortality.
- By 15 years, cumulative CHD mortality increased progressively with higher SBP categories, and elevated SBP (> or = 140 mm Hg) was associated with a ~40% higher mortality rate regardless of DBP.
Conclusions:
- The association between blood pressure and mortality in men post-MI is dynamic, changing over time.
- While early follow-up in older men showed a J-shaped curve, sustained high SBP (> or = 140 mm Hg) after two years poses a significant, graded mortality risk.
- Aggressive blood pressure management, particularly lowering SBP, is a high priority for hypertensive men with a history of MI to mitigate excess mortality risk.
Background:
The purpose of the present study was to describe the relation between blood pressure (systolic [SBP] and diastolic [DBP]) and death from coronary heart disease (CHD) and all causes for men with a history of myocardial infarction (MI).
Methods And Results:
The study cohort consisted of men aged 35 to 57 years screened for the Multiple Risk Factor Intervention Trial (MRFIT) in 1973 through 1975 and followed for survival for an average of 16 years through 1990. There were 5362 men who reported prior hospitalization for a heart attack of at least 2 weeks' duration at the initial screening of MRFIT. There was a J-shaped relation between SBP and DBP with both CHD and all-cause mortality during the first 2 years of follow-up in older (age, 45 to 57 years) men only. Risk nadirs for SBP were 152 and 145 mm Hg, respectively, for CHD death and all-cause mortality; corresponding DBP risk nadirs were 94 and 90 mm Hg. After the first 2 years, there was a positive association between SBP and death from CHD and all causes. By 15 years, cumulative CHD mortality percentages for men with screening SBP < 120, 120 to 139, 140 to 159, and > or = 160 mm Hg were 19.7%, 21.3%, 27.5%, and 32.0%, respectively. When deaths only after year 2 were considered, although the linear DBP coefficient was significant, the quadratic term for DBP was no longer significant (P > .05). However, the relation still appeared J-shaped as cumulative mortality for those with DBP < 70, 70 to 79, 80 to 89, 90 to 99, and > or = 100 mm Hg was 24.3%, 20.8%, 21.1%, 25.5%, and 29.7%, respectively. When the joint relation of SBP and DBP was considered, there were no survival differences among the four cohorts (SBP > or = 140 and DBP < 80, SBP > or = 140 and DBP > or = 80, SBP < or = 140 and DBP < 80, and SBP < or = 140 and DBP > or = 80) during the first 2 years. After 2 years, both CHD and all-cause mortality rates were approximately 40% higher for participants with SBP > or = 140 mm Hg versus < 140 mm Hg regardless of DBP level (< 80 or > or = 80 mm Hg).
Conclusions:
In this large cohort of men with prior MI, the association of SBP and DBP with CHD and all-cause mortality varied over the 16-year follow-up period. During early follow-up, in older men only, J- or U-shaped relations were evident. However, after 2 years, these same relations had become positive and graded. Given the substantial excess mortality risk in this cohort associated with high blood pressure, particularly SBP, efforts to gradually lower blood pressure should receive high priority among hypertensive men with prior MI.