Angiotensin receptor blocker therapy was not associated with any hint of increased risk of suicide, compared with treatment with an ACE inhibitor, in a large national Veterans Affairs study, Kallisse R. Dent, MPH, reported at the virtual annual meeting of the American Association of Suicidology.
The VA study thus fails to confirm the results of an earlier Canadian, population-based, nested case-control study, which concluded that exposure to an angiotensin receptor blocker (ARB) was independently associated with an adjusted 63% increase risk of death by suicide, compared with ACE inhibitor users. The Canadian study drew considerable attention, noted Ms. Dent, of the VA Office of Mental Health and Suicide Prevention.
The Canadian study included 964 Ontario residents who died by suicide within 100 days of receiving an ACE inhibitor or ARB. They were matched by age, sex, and the presence of hypertension and diabetes to 3,856 controls, all of whom were on an ACE inhibitor or ARB for the 100 days prior to the patient’s suicide. All subjects were aged at least 66 years.
The Canadian investigators recommended that ACE inhibitors should be used instead of ARBs whenever possible, particularly in patients with major mental illness (JAMA Netw Open. 2019 Oct 2;2[10]:e1913304). This was a study that demanded replication because of the enormous potential impact that recommendation could have upon clinical care. ACE inhibitors and ARBs are among the most widely prescribed of all medications, with approved indications for treatment of hypertension, chronic kidney disease, diabetes, and heart failure, Ms. Dent observed.
The Canadian investigators noted that a differential effect on suicide risk for the two drug classes was mechanistically plausible. Those drugs can cross the blood-brain barrier to varying extents, where they could conceivably interfere with central angiotensin II activity, which in turn could result in increased activity of substance P, as well as anxiety and stress secondary to increased activity of the hypothalamic-pituitary-adrenal axis.
Ms. Dent and coinvestigators harnessed VA suicide surveillance resources to conduct a nested case-control study that included all 1,311 deaths by suicide during 2015-2017 among patients in the VA system who had an active prescription for an ACE inhibitor or ARB during the 100 days immediately prior to death. As in the Canadian study, these individuals were matched 4:1 to 5,243 controls who did not die by suicide and had an active prescription for an ARB or ACE inhibitor during the 100 days prior to the date of suicide.
Those rates were not significantly different from the rates found in controls, 21.6% of whom were on an ARB and 78.4% were on an ACE inhibitor. In a multivariate analysis adjusted for the same potential confounders included in the Canadian study – including Charlson Comorbidity Index score; drug use; and diagnosis of alcohol use disorder, coronary artery disease, stroke, and chronic liver or kidney disease – being on an ARB was associated with a 9% lower risk of suicide than being on an ACE inhibitor, a nonsignificant difference.
A point of pride for the investigators was that, because of the VA’s sophisticated patient care database and comprehensive suicide analytics, the VA researchers were able to very quickly determine the lack of generalizability of the Canadian findings to a different patient population. Indeed, the entire VA case-control study was completed in less than 2 months.
Ms. Dent reported having no financial conflicts regarding the study, which was sponsored by the Department of Veterans Affairs.