In older age, a low DBP has been associated with increased risk of cardiovascular events, especially in frail older people. We tested the hypothesis that low DBP is associated with a high risk of cardiovascular events in people with a previous history of cardiovascular disease, as a proxy of vascular impairment.
We included 5804 participants (mean age 75 years) from the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) who as part of the trial were intensively monitored for an average period of 3.2 years. DBP was categorized in low (<70 mmHg), normal (70–90 mmHg) or high (>90 mmHg). Cox proportional hazards analyses were used to estimate hazard ratio with 95% confidence intervals (CI); analyses were stratified for cardiovascular history.
Participants with low DBP had a 1.24-fold (1.04; 1.49) increased risk of cardiovascular events compared with those with normal DBP. After further adjusting for cardiovascular factors, this association attenuated to 1.05 (0.86; 1.28). A previous history of cardiovascular disease significantly modified the relation between DBP and risk of cardiovascular events (P-interaction 0.042). In participants without a history of cardiovascular disease, DBP was marginally significantly associated with an increased event risk (hazard ratio (95% CI) per 10 mmHg increase in DBP 1.08 (0.99; 1.18), P value = 0.07), whereas in participants with a history of cardiovascular disease, higher DBP was associated with a decreased risk of cardiovascular events (hazard ratio (95% CI) per 10 mmHg increase in DBP 0.92 (0.85; 0.99, P value = 0.018). These risk estimates were independent of potential confounders, including classical cardiovascular risk factors.
The association of DBP with cardiovascular events in older people varies upon their previous history, showing that in participants with preexisting cardiovascular diseases, a higher DBP associates with a decreased risk of future cardiovascular events.
aDepartment of Gerontology and Geriatrics, Leiden University Medical Center, Leiden
bDepartment of Internal Medicine, VU University Medical Center, Amsterdam
cDepartment of Cardiology, Leiden University Medical Center, Leiden, the Netherlands
dDepartment of Public Health, Center for Healthy Ageing, University of Copenhagen, Copenhagen, Denmark
eInstitute for Evidence-Based Medicine in Old Age, Leiden, the Netherlands
Correspondence to Simon P. Mooijaart, MD, PhD, Department of Gerontology and Geriatrics, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands. Tel: +31 715264476; fax: +31 715266912; e-mail: S.P.Mooijaart@lumc.nl
Abbreviations: CI, confidence interval; cTnT, cardiac troponin T; eGFR, estimated glomerular filtration rate; HDL, high-density lipoprotein; LDL, low-density lipoprotein; NT-proBNP, N-terminal pro-brain natriuretic peptide; PROSPER, PROspective Study of Pravastatin in the Elderly at Risk; P value, probability value
Received 25 January, 2017
Revised 7 August, 2017
Accepted 24 October, 2017
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