Calcium channel blockers versus other classes of drugs for hypertension.
BACKGROUND
Calcium channel blockers (CCBs) are a relatively new antihypertensive class. The effect of first-line CCBs on the prevention of cardiovascular events, as compared with other antihypertensive drug classes, is unknown.


OBJECTIVE
To determine whether CCBs used as first-line therapy for hypertension are different from other first-line drug classes in reducing the incidence of major adverse cardiovascular events.


METHODS
Electronic searches of the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASEand the WHO-ISH Collaboration Register (up to May 2009) were performed. We also checked the references of published studies to identify additional trials.


METHODS
Randomized controlled trial (RCT) comparing first-line CCBs with other antihypertensive classes, with at least 100 randomized hypertensive participants and with a follow-up of at least two years.


METHODS
Two authors independently selected the included trials, evaluated the risk of bias and entered the data for analysis.


RESULTS
Eighteen RCTs (14 dihydropyridines, 4 non-dihydropyridines) with a total of 141,807 participants were included. All-cause mortality was not different between first-line CCBs and any other first-line antihypertensive classes. CCBs reduced the following outcomes as compared to beta-blockers: total cardiovascular events (RR 0.84, 95% CI [0.77, 0.92]), stroke (RR 0.77, 95% CI [0.67, 0.88]) and cardiovascular mortality (RR 0.90, 95% CI [0.81, 0.99]). CCBs increased total cardiovascular events (RR 1.05 , 95% CI [1.00, 1.09], p = 0.03) and congestive heart failure events (RR 1.37, 95% CI [1.25, 1.51]) as compared to diuretics. CCBs reduced stroke (RR 0.89, 95% CI [0.80, 0.98]) as compared to ACE inhibitors and reduced stroke (RR 0.85, 95% CI [0.73, 0.99]) and MI (RR 0.83, 95% CI [0.72, 0.96]) as compared to ARBs. CCBs also increased congestive heart failure events as compared to ACE inhibitors (RR 1.16, 95% CI [1.06, 1.27]) and ARBs (RR 1.20, 95% CI [1.06, 1.36]). The other evaluated outcomes were not significantly different.


CONCLUSIONS
Diuretics are preferred first-line over CCBs to optimize reduction of cardiovascular events. The review does not distinguish between CCBs, ACE inhibitors or ARBs, but does provide evidence supporting the use of CCBs over beta-blockers. Many of the differences found in the current review are not robust and further trials might change the conclusions. More well-designed RCTs studying the mortality and morbidity of patients taking CCBs as compared with other antihypertensive drug classes are needed for patients with different stages of hypertension, different ages, and with different co-morbidities such as diabetes.
Chen
Ning
N
Department of Neurology, West China Hospital, Sichuan University, Wai Nan Guo Xue Xiang #37, Chengdu, Sichuan, China, 610041.
Zhou
Muke
M
Yang
Mi
M
Guo
Jian
J
Zhu
Cairong
C
Yang
Jie
J
Wang
Yucai
Y
Yang
Xue
X
He
Li
L
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D002318:Cardiovascular Diseases / Q000517:prevention & control; D002423:Cause of Death; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic; D049993:Sodium Chloride Symporter Inhibitors / Q000627:therapeutic use
D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D049993:Sodium Chloride Symporter Inhibitors