Twenty eight studies (n=5,157 patients) were included. One trial scored 5 on the Jadad score, seven scored 4, seven scored 3, seven scored 2 and six scored 1. Allocation concealment was adequate in two trials, inadequate in seven trials and unclear in the other trials. Thirteen trials were double blind and six were single blind. Ten studies used an intention-to-treat analysis.
Telmisartan versus enalapril (13 RCTs, n=1,682): Both diastolic blood pressure (WMD 1.82, 95% CI 0.66 to 2.99) and systolic blood pressure (WMD 3.63, 95% CI 1.59 to 5.68) showed significantly greater reductions in patients treated with telmisartan compared to those treated with enalapril. Therapeutic response rates were significantly greatly for telmisartan for both diastolic blood pressure (RR 1.15, 95% CI 1.05 to 1.26) and systolic blood pressure (RR 1.18, 95% CI 1.02 to 1.38). Restriction of the analysis to high-quality trials showed a similar effect on diastolic blood pressure.
Telmisartan versus ramipril (six RCTs, n=1,881): There was a significantly greater reduction in diastolic blood pressure (WMD 3.09, 95% CI 1.94 to 4.25) in patients treated with telmisartan compared to those treated with enalapril; there was no significant difference in systolic blood pressure. Therapeutic response rates were significantly greater for telmisartan for both diastolic blood pressure (RR 1.34, 95% CI 1.11 to 1.61) and systolic blood pressure (RR 1.16, 95% CI 1.08 to 1.24). Restriction of the analysis to high-quality trials showed a similar effect on diastolic blood pressure.
Telmisartan versus lisinopril (four RCTs, n=886): There was no significant difference in diastolic blood pressure reduction or therapeutic response rate of diastolic blood pressure between the two groups. Systolic blood pressure (WMD -1.09, 95% CI -1.58 to -0.61) showed a significantly smaller reduction in patients treated with telmisartan compared to those treated with lisinopril.
Telmisartan versus perindopril (five RCTs, n=708): Diastolic blood pressure (WMD 1.48, 95% CI 0.33 to 2.62) and therapeutic response rate in diastolic blood pressure (RR 1.22, 95% CI 1.05 to 1.41) showed significantly greater reductions in patients treated with telmisartan compared to those treated with perindopril; there was no significant difference in systolic blood pressure.
Adverse events: Telmisartan caused fewer adverse events (RR 0.78, 95% CI 0.66 to 0.91), drug-related adverse events (results not reported), adverse events-related withdrawals (RR 0.62, 95% CI 0.46 to 0.85) and cough (RR 0.23, 95% CI 0.17 to 0.33) than the four other ACE inhibitors assessed. No patients suffered from angioedema in the telmisartan groups, but two patients did in each of the lisinopril group and enalapril group. There were no deaths or cerebro-cardiovascular events in any group.