Abstract P014: Impact of Antihypertensive Class on Central Systolic Blood Pressure and Augmentation Index: A Meta-Analysis

Abstract

Introduction: New evidence suggests central systolic blood pressure (cSBP) is a superior predictor of adverse cardiovascular outcomes as compared to peripheral systolic blood pressure (pSBP). Additionally, augmentation index (AI) provides a surrogate assessment of vascular stiffness. We performed a meta-analysis to assess the impact of antihypertensive drug classes on cSBP and AI. METHODS: Search terms related to blood pressure and AI were used to identify relevant articles in PubMed, Cochrane Library and CINAHL limited to randomized trials in humans and publications in English. Appropriate data on cSBP, pSBP and AI were extracted along with other study characteristics. Weighted mean differences (WMD) between the pSBP and cSBP with 95% confidence intervals (CI) were calculated using the DerSimonian-Laird random-effects methodology. For AI, the WMD from baseline was determined. Further, the data was sorted by antihypertensive class (angiotensin converting enzyme inhibitors (ACE-Is), angiotensin II receptor blockers (ARBs), beta-blockers (BBs), calcium channel blockers (CCBs) and diuretics) to determine their impact on cSBP and AI. Subgroup analyses were performed to assess robustness of results by limiting to the fixed-effects model, a primary diagnosis of hypertension, and excluding studies with JADAD scores < 3. Publication bias was assessed using the Egger’s statistic and visual inspection of funnel plots. Statistical heterogeneity was assessed using the I2 statistic. RESULTS: Fifty-one and 58 studies incorporating 4381 and 3716 unique subjects were included for cSBP and AI respectively. Overall, antihypertensives reduced pSBP more than cSBP (2.52mmHg, 95%CI 1.35 to 3.69; I2 =21.9%). ACE-Is, ARBs, CCBs and diuretics reduced cSBP and pSBP in a similar manner (-2.40mmHg, 95%CI -4.89 to 0.08; 1.12mmHg, 95%CI -2.25 to 4.49; 1.01mmHg, 95%CI -2.17 to 4.19; 0.65mmHg, 95%CI -2.47 to 3.77 respectively). BBs posed a significantly greater reduction in pSBP as compared to cSBP (5.19mmHg, 95%CI 3.21 to 7.18). The change in AI from baseline was (-3.09, 95%CI -3.90 to -2.28; I2 =84.5%). A significant reduction in AI was seen with ACE-Is, ARBs, CCB and diuretics (-5.61, 95%CI -6.95 to -4.27; -5.28, 95%CI -8.61 to -1.95; -5.36, 95%CI -6.95 to -3.77; -3.24, 95%CI -5.45 to -1.03 respectively). BBs reduced AI non-significantly (-0.32, 95% CI -1.48 to 0.84). While the Egger’s statistic showed a lack of publication bias (p>0.125), it cannot be ruled out based on visual inspection of funnel plots. CONCLUSIONS: BBs are not as beneficial in reducing cSBP as opposed to ACE-Is, ARBs, CCBs and diuretics. In contrast, ACE-Is, ARBs, CCBs and diuretics significantly reduce AI, which is not evident with BB therapy. The views expressed in this material are those of the author(s), and do not reflect the official policy or position of the U.S. Government, the Department of Defense, or the Department of the Air Force.