The results of some previous trials indicated a possibility that ARBs may increase the risk of myocardial infarction. This review identified 37 randomised clinical trials included 147,020 participants and had a total follow-up of 485,166 patient years. The trials included both placebo and active comparator designs. The analysis was performed on all studies and the differing design type were also analysed separately. Studies were required to have at least 100 participants and run for at least 12 months. Data were collected and analysed for several outcomes including myocardial infarction, death, cardiovascular death, angina pectoris, stroke, heart failure and new onset diabetes.
This review found that when ARBs are compared with either placebo or a control treatment there is a lesser risk of stroke, heart failure and new onset diabetes. It was also found that when ARBs are compared to placebo, and despite lower average blood pressures, there is no decrease in the risk of myocardial infarction or cardiovascular death.
The authors note that, "unlike angiotensin converting enzyme inhibitors seem not to have any special “cardioprotective” effects". They also conclude that, "this large and comprehensive analysis produced firm evidence to refute the hypothesis that angiotensin receptor blockers increase the risk of myocardial infarction".
There are some limitations to this analysis. A lack of data from the studies meant that no correction could be made for the dose of drugs used or compliance with assigned treatment. Additionally, this was not an analysis of individual patient data and therefore clinically relevant differences could have been overlooked.
Action: This analysis provides some reassurance that ARBs do not cause cardiovascular harms. However, this analysis found no beneficial effect on the rate of cardiovascular death or myocardial infarction when compared to placebo. ARBs therefore remain an alternative for consideration in patients who are angiotensin converting enzyme inhibitor (ACEI) intolerant.