Six RCTs were identified (n=3,762 patients, range 70 to 1,051). Three trials had blinding of both investigators and participants; the other RCTs were open-label, two of which were endpoint blind for both assessors and participants. Four RCTs had an intention-to-treat analysis. Allocation concealment was adequate in five RCTs. Loss to follow-up ranged from 0 to 11.5%. Follow-up was for six to 12 weeks in all but one trial (where it was 52 weeks).
Blood pressure change from baseline: A 80mg/day dose of telmisartan was found to have a comparable effect in lowering blood pressure to 160mg/day valsartan in monotherapy (no relevant data provided). There was no difference between telmisartan and valsartan in reduction of systolic blood pressure (WMD -1.01mmHg, 95% CI -3.38 to 1.36; I2=95%) or reduction of diastolic blood pressure (WMD -0.39mmHG, 95% CI -2.24 to 1.45; I2=98%) for all six trials. Subgroup analyses found, when the drugs were combined with hydrochlorothiazide, telmisartan was significantly more effective than valsartan in reducing both systolic blood pressure (WMD -2.88mmHg, 95% CI -5.03 to -0.73; I2=70%) and diastolic blood pressure (WMD -1.73mmHg, 95% CI -2.47 to -0.98; I2=40%) for two trials. The result was still not significant for the four trials that did not additionally use hydrochlorothiazide, with a high level of heterogeneity (I2=96% and I2=98%).
Target bllod pressure achievement: There was no significant difference between telmisartan and valsartan in achieving the target blood pressure (four RCTs; I2=0%) or for the subgroup analysis of the trials which did not additionally use hydrochlorothiazide (two RCTs; I2=0%). However, when the drugs were combined with hydrochlorothiazide, telmisartan was significantly more effective than valsartan in achieving the target blood pressure (RR 1.09, 95% CI 1.00 to 1.19; two RCTs; I2=0%).
Safety: There were no significant differences in the incidence of adverse events for telmisartan compared with valsartan for headache (four RCTs; I2=0%), dizziness (three RCTs; I2=35%), infections (four RCTs; I2=64%), or pain (two RCTs; I2=0%). The incidence of reported adverse events ranged from 30 to 70%.