The quality of evidence is downgraded by study limitations (unclear allocation concealment), by inconsistency (unexplained variability in results), and by imprecise results (few outcome events and wide confidence intervals).
A Cochrane review [Abstract] 1 included 3 studies with a total of 8 221 subjects (mean age 74.8 years). Higher blood pressure (BP) targets (less than 150/90 mmHg in 2 studies and less than 160/90 mmHg in 1 study) were compared to a lower target of less than 140/90 mmHg. Study duration varied between 2 to 4 years. Meta-analyses comparing higher vs. lower BP target failed to produce a difference in any of the primary outcomes, including all-cause mortality (RR 1.24 95% CI 0.99 to 1.54, statistical heterogeneity I2 =79%; 3 studies, n=8 221), stroke (RR 1.25 95% CI 0.94 to 1.67; 3 studies, n=8 221) and total cardiovascular serious adverse events (cerebrovascular disease, cardiac disease, vascular disease and renal failure; RR 1.19 95% CI 0.98 to 1.45, statistical heterogeneity, I2 =59%; 3 studies, n=8 221). Pooling data for cardiovasculafr mortality (secondary outcome) produced a statistically significant difference showing the higher target to be inferior (RR 1.52, 95% CI 1.06 to 2.19, statistical heterogeneity I2 =52%; 3 studies, n= 8221). Data on adverse effects were not available from all trials and not different, including total serious adverse events, total minor adverse events, and withdrawals due to adverse effects.
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