ACE Inhibitors Protective Against Severe COVID-19?

May 20, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

A new nationwide US observational study suggests that ACE inhibitors may protect against severe illness in older people with COVID-19, prompting the start of a randomized clinical trial to test the strategy.

In addition, a new meta-analysis of all the available data on the use of ACE inhibitors and angiotensin-receptor blockers (ARBs) in COVID-19–infected patients has concluded that these drugs are not associated with more severe disease and do not increase susceptibility to infection.

The observational study, which was published on the MedRxiv preprint server on May 19 and has not yet been peer reviewed, was conducted by the health insurance company United Heath Group and by the Yale University School of Medicine, in New Haven, Connecticut.

The investigators analyzed data from 10,000 patients from across the United States who had tested positive for COVID-19, who were enrolled in Medicare Advantage insurance plans or were commercially insured, and who had received a prescription for one or more antihypertensive medications.

Results showed that the use of ACE inhibitors was associated with an almost 40% lower risk for COVID-19 hospitalization for older people enrolled in Medicare Advantage plans. No such benefit was seen in the younger commercially insured patients or in either group with ARBs.

At a telephone media briefing on the study, senior investigator Harlan Krumholz, MD, said: "We don't believe this is enough info to change practice, but we do think this is an interesting and intriguing result.

"These findings merit a clinical trial to formally test whether ACE inhibitors ― which are cheap, widely available, and well-tolerated drugs ― can reduce hospitalization of patients infected with COVID-19," he added.

Krumholz is professor of medicine at Yale and is the director of the Yale New Haven Hospital Center for Outcomes Research.

A pragmatic clinical trial is now being planned. In this trial, 10,000 older people who test positive for COVID-19 will be randomly assigned to receive either a low dose of an ACE inhibitor or placebo. It is hoped that recruitment for the trial will begin within the next 3 to 4 weeks. It is open to all eligible Americans who are older than 50 years, who test negative for COVID-19, and who are not taking medications for hypertension. Prospective patients can sign up at a dedicated website.

The randomized trial, also conducted by United Health Group and Yale, is said to be "one of the first virtual COVID-19 clinical trials to be launched at scale."

For the observational study, the researchers identified 2263 people who were receiving medication for hypertension and who tested positive for COVID-19. Of these, approximately two thirds were older, Medicare Advantage enrollees; one third were younger, commercially insured individuals.

In a propensity score–matched analysis, the investigators matched 441 patients who were taking ACE inhibitors to 441 patients who were taking other antihypertensive agents; and 412 patients who were receiving an ARB to 412 patients who were receiving other antihypertensive agents.

Results showed that during a median of 30 days after testing positive, 12.7% of the cohort were hospitalized for COVID-19. In propensity score–matched analyses, neither ACE inhibitors (hazard ratio [HR], 0.77; P = .18) nor ARBs (HR, 0.88; P =.48) were significantly associated with risk for hospitalization.

However, in analyses stratified by insurance group, ACE inhibitors (but not ARBs) were associated with a significant lower risk for hospitalization among the Medicare group (HR, 0.61; P = .02) but not among the commercially insured group (HR, 2.14; P = .12).

A second study examined outcomes of 7933 individuals with hypertension who were hospitalized with COVID-19 (92% of these patients were Medicare Advantage enrollees). Of these, 14.2% died, 59.5% survived to discharge, and 26.3% underwent ongoing hospitalization. In propensity score–matched analyses, use of neither an ACE inhibitor (HR, 0.97; P = .74) nor an ARB (HR, 1.15; P = .15) was associated with risk of in-hospital mortality.

The researchers say their findings are consistent with prior evidence from randomized clinical trials suggesting a reduced risk for pneumonia with ACE inhibitors that is not observed with ARBs.

They also cite some preclinical evidence that they say suggests a possible protective role for ACE inhibitors in COVID-19: that ACE inhibitors, but not ARBs, are associated with the upregulation of ACE2 receptors, which modulate the local interactions of the renin-angiotensin-aldosterone system in the lung tissue.

"The presence of ACE2 receptors, therefore, exerts a protective effect against the development of acute lung injury in infections with SARS coronaviruses, which lead to dysregulation of these mechanisms and endothelial damage," they add. "Further, our observations do not support theoretical concerns of adverse outcomes due to enhanced virulence of SARS coronaviruses due to overexpression of ACE2 receptors in cell cultures – an indirect binding site for these viruses."

The authors also note that their findings have "important implications" for four ongoing randomized trials of ACE inhibitors/ARBs in COVID-19, "as none of them align with the observations of our study."

They point out that of the four ongoing trials, three are testing the use of ACE inhibitors or ARBs in the treatment of hospitalized COVID-19 patients, and one is testing the use of a 10-day course of ARBs after a positive SARS-CoV-2 test to prevent hospitalization.

Experts Cautious

However, two cardiovascular experts who were asked to comment on this latest study for Medscape Medical News were not overly optimistic about the data.

Michael Weber, MD, professor of medicine at the State University of New York, said: "This report adds to the growing number of observational studies that show varying effects of ACE inhibitors and ARBs in increasing or decreasing hospitalizations for COVID-19 and the likelihood of in-hospital mortality. Overall, this new report differs from others in the remarkable effects of insurance coverage: in particular, for ACE inhibitors, there was a 40% reduction in fatal events in Medicare patients but a twofold increase in patients using commercial insurance ― albeit the test for heterogeneity when comparing the two groups did not quite reach statistical significance.

"In essence, these authors are saying that ACE inhibitors are highly protective in patients aged 65 or older but bordering on harmful in patients aged below 65. I agree that it's worthwhile to check this finding in a prospective trial...but this hypothesis does seem to be a reach."

Weber noted that both ACE inhibitors and ARBs increase the level of the ACE2 enzyme to which the COVID-19 virus binds in the lungs.

"The ACE inhibitors do so by inhibiting the enzyme's action and thus stimulate further enzyme production; the ARBs block the effects of angiotensin II, which results in high angiotensin II levels that also upregulate ACE2 production," he said. "Perhaps the ACE inhibitors, by binding to the ACE enzyme, can in some way interfere with the enzyme's uptake of the COVID virus and thus provide some measure of clinical protection. This is possible, but why would this effect be apparent only in older people?"

John McMurray, MD, professor of medical cardiology at the University of Glasgow, added: "This looks like a subgroup of a subgroup type analysis based on small numbers of events ― I think there were only 77 hospitalizations among the 722 patients treated with an ACE inhibitor, and the Medicare Advantage subgroup was only 581 of those 722 patients.

"The hazard ratio had wide 95% CI [confidence interval] and a modest P value," Murray added. "So yes, interesting and hypothesis-generating, but not definitive."

New Meta-analysis

The new meta-analysis of all data so far available on ACE inhibitor and ARB use for patients with COVID-19 was published online in Annals of Internal Medicine on May 15.

The analysis is a living systematic review with ongoing literature surveillance and critical appraisal, which will be updated as new data become available. It included 14 observational studies.

The authors, led by Katherine Mackey, MD, VA Portland Health Care System, Oregon, conclude: "High-certainty evidence suggests that ACE-inhibitor or ARB use is not associated with more severe COVID-19 disease, and moderate certainty evidence suggested no association between use of these medications and positive SARS-CoV-2 test results among symptomatic patients. Whether these medications increase the risk for mild or asymptomatic disease or are beneficial in COVID-19 treatment remains uncertain."

In an accompanying editorial, William G. Kussmaul, MD, Drexel University College of Medicine, Philadelphia, Pennsylvania, says that initial fears that these drugs may be harmful for patients with COVID-19 now seem to have been unfounded.

"We now have reasonable reassurance that drugs that alter the renin angiotensin system do not pose substantial threats as either COVID-19 risk factors or severity multipliers," he writes.

MedRxiv. Published online May 19, 2020. Full text

Ann Intern Med 2020. Published online May 15, 202. Full text, Editorial

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