Research suggests ACE inhibitors have a higher mortality and MACE risk than ARBs, but Australian expert says the data is not ‘up to it’.
Patients who take ACE inhibitors may have a higher risk of five-year mortality and major adverse cardiovascular events than those who take ARBs, research suggests.
The cohort study included 72,000 patients from the UK and 255,000 from China who were newly prescribed either ACE (angiotensin-converting enzyme) inhibitors or ARBs (angiotensin receptor blockers).
The researchers found that at the five-year follow-up, new users of ARBs had a lower risk of all-cause mortality compared with new users of ACE inhibitors.
After five-years, there were 696 all-cause deaths (3.45%) among UK ACE inhibitor users, and 630 all-cause deaths (3.04%) among UK ARBs users.
The researchers said all-cause mortality was also higher among UK patients who took ACE inhibitors at the 10-year and 15-year follow-up compared with ARB initiators.
And in the Chinese database, the five-year cumulative incidence of all-cause mortality was 16% for ACE inhibitors initiators and 15% for ARBs initiators.
“The reduced mortality risk associated with ARBs use may partly be explained by a lower incidence of MACE,” the researchers said in Hypertension.
The findings highlight the importance of carefully weighing the selection of renal angiotensin-aldosterone system inhibitors and considering effectiveness and safety, they said.
But cardiologist and professorial research fellow at the Baker Heart and Diabetes Institute, Professor Thomas Marwick, said the research contained unmeasured cofounders and while the cohort numbers were large, the baseline characteristics of participants in the UK and Chinese databases were “fundamentally different”.
For instance, mean BMI was 29 in the UK cohort and 21 in the Chinese cohort, while LDL cholesterol was 1.6 in the UK group and 2.7 for Chinese participants.
Professor Marwick noted that rates of heart failure also differed between the two groups: 2% of UK participants were being treated for heart failure, compared with 18% of the Chinese cohort.
“The numbers obviously are huge, which is the attraction, but the disadvantage is that the granularity of the data is not enough to make what is a really important distinction. I just don’t think the data is up to it,” he told The Medical Republic.
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Professor Marwick said ACE inhibitors and ARBs were of “comparable efficacy” when treating hypertension.
“Each of them have got somewhat different side effects. Probably the ARBs are better tolerated, and the ARBs, I would say, are probably generally preferred in general practice.
“But what they’ve given us here is a comparison of the use of the agents, not necessarily for hypertension, in databases where the associated risks of the patients are actually quite different, so you’re asking the statistical modelling to try and overcome some pretty significant differences in the profiles of the patients. And I think it’s too much to ask the stats to do.”
Professor Marwick said the results could be “hypothesis generating, but I don’t think that they’re conclusive”.
“It’s a reminder of the limitation of observational data sets, that you can crank up big numbers but you’ve got to be really careful about whether that corresponds to what the question is in practice.”
