Efficacy and Safety of Angiotensin-Based Pharmacotherapy versus Conventional Therapy for the Management of Isolated Systolic Hypertension: A Meta-Analysis of Randomized Controlled Trials

The angiotensin (AT) system is highly implicated in the pathophysiology of isolated systolic hypertension (ISH). Consequently, this meta-analysis was designed to quantitatively review the efficacy and safety of angiotensin (AT)-based regimens in comparison with conventional thiazide diuretics or calcium channel blockers (CCBs) for the management of ISH. MEDLINE and CENTRAL were searched for relevant randomized controlled trials (RCTs). The outcomes assessed were blood pressure (BP) reduction, mortality, myocardial infarction (MI), stroke, and adverse events (AEs). Statistical analysis was carried out as recommended by the Cochrane Collaboration using data weighted mean difference (WMD) and relative risk (RR). Fourteen studies involving 6296 patients met the selection criteria for inclusion in this meta-analysis. There was no beneficial fall in systolic BP using AT inhibitors versus diuretics or CCBs (WMD = 0.09, 95% confidence interval (CI) -1.02 – 1.21, P = 0.87). In addition, AT inhibitors did not adversely lower the diastolic BP compared to diuretics or CCBs. There was also no significant reduction by the AT inhibitors in the primary efficacy outcomes including mortality, MI and stroke. Interestingly, AT inhibition demonstrated a significantly lower incidence of AEs better than conventional therapy (RR = 0.66, 95% CI 0.5 - 0.87, P = 0.003). Therefore, there is strong evidence to conclude the comparative effectiveness of AT inhibition versus thiazide-induced diuresis or calcium antagonism regarding efficacy outcomes. There is also sufficient evidence to recommend AT inhibition as initial choice with regard to its safety for the management of ISH in adults.