Isolated diastolic hypertension and cardiovascular outcomes across different diagnostic guidelines: a systematic review and meta-analysis

Background This systematic review aims to determine the impact of isolated diastolic hypertension (IDH) on cardiovascular outcomes. Methods We searched only English language articles on PubMed and SCOPUS until July 31, 2023 to investigate the association between IDH and cardiovascular outcomes. Results This meta-analysis of 19 studies evaluated the impact of different hypertension diagnostic guidelines (ACC/AHA: American Heart Association/American College of Cardiology; JNC7: Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure; NICE/ESC: National Institute for Health and Care Excellence/European Society of Cardiology) on hypertension-related outcomes. Studies had varying sample sizes (173 to 2,969,679 participants) and study designs. In cohort studies using JNC7 guidelines, IDH was linked to increased cardiovascular disease (CVD) risk (HR: 1.45, 95% CI 1.17, 1.74), CVD mortality (HR: 1.54, 95% CI 1.23, 1.84), and coronary heart disease (CHD) risk (HR: 1.65). In studies using ACC/AHA guidelines, associations with CVD risk and CVD mortality were weaker [HR: 1.16 (95% CI 1.06, 1.25) and 1.10 (95% CI 0.95, 1.25), respectively]. Subgroup analysis revealed differences in outcomes on the basis of age and sex. Cross-sectional studies did not show significant associations with JNC7 and ACC guidelines; NICE guidelines were not used in cross-sectional studies. Conclusion IDH is associated with an increased risk of CVD. Higher diastolic blood pressure cutoffs were associated with higher cardiovascular risk. This association varied by study design and effect modification by sex and race influenced the association.