Isolated Systolic Hypertension in Young/Middle-Aged Adults and 31-Year Risk of Cardiovascular Mortality: The Chicago Heart Association Detection Project in Industry Study | Journal Scan

Study Questions:

Does isolated systolic hypertension (ISH), defined as systolic blood pressure (SBP) ≥140 mm Hg and diastolic BP (DBP) <90 mm Hg, increase the risk of cardiovascular (CV) events in younger and middle-aged adults?


The Chicago Heart Association Detection Project in Industry Study group assessed the risk of CV disease (CVD) in 15,868 men and 11,213 women 18-49 years of age (mean age 34 years) at baseline, 85% non-Hispanic white, free of coronary heart disease (CHD) and antihypertensive therapy. Participant classifications were: 1) optimal-normal BP (SBP <130 and DBP <85 mm Hg); 2) high-normal BP (130-139/85-89 mm Hg); 3) ISH; 4) isolated diastolic hypertension (IDH; SBP <140 and DBP ≥90 mm Hg); and 5) systolic diastolic hypertension (SDH; SBP ≥140 and DBP ≥90 mm Hg.


During a 31-year average follow-up (842,600 person-years), there were 1,728 deaths from CVD, 1,168 from CHD and 223 from stroke. Cox proportional hazards models were adjusted for: age, race, education, body mass index, current smoking, total cholesterol, and diabetes. In men, with optimal-normal BP as the reference stratum, hazard ratios (HRs) and 95% confidence intervals (CIs) of CVD and CHD mortality risk for those with ISH were 1.23 (1.03-1.46) and 1.28 (1.04-1.58), respectively. ISH risks were similar to those with high-normal BP and less than those associated with IDH/SDH. In women with ISH, HRs (95% CIs) of CVD and CHD mortality risk were 1.55 (1.18-2.05) and 2.12 (1.49-3.01), respectively. ISH risks were higher than in those with high-normal BP/IDH, and less than as those associated with SDH.


Over long-term follow-up, younger and middle-aged adults with ISH had higher relative risk of CVD and CHD mortality than those with optimal-normal BP.


The study is novel in that few studies have evaluated the impact of ISH among a younger cohort and directly compared it with other groups. The findings demonstrate that the hemodynamics of ISH are not innocent, even among a younger cohort, and that treatment of ISH among younger lower-risk patients may need to be tested. Large long-term prospective population studies provide insight into the relative importance of the range of CVD risk factors within cohorts. Among the limits of generalizability and usefulness include the changing methods of measuring clinical variables (e.g., BP), change in lifestyle effect on risk factors, improvement in medical therapies, unavailability of clinical parameters at follow-up time points, and the inability to verify clinical endpoints except for mortality.

Clinical Topics: Heart Failure and Cardiomyopathies

Keywords: Blood Pressure, Coronary Disease, Diastole, Systole, Risk, Middle Aged, Follow-Up Studies

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