Cannabis use did not reduce mortality in veterans on opioids, and increased risk in older adults | Research

The takeaway

Among nearly 300,000 veterans prescribed opioids, cannabis use did not reduce mortality overall but was associated with increased 90-day mortality in adults over 65 on long-term opioid therapy.

Veterans using cannabis with opioids, VA clinicians, pain management specialists, and policymakers evaluating cannabis as an opioid alternative.

55% increased mortality risk in seniors on long-term opioids

What the researchers found

Cannabis use was not associated with all-cause mortality at 90 or 180 days in the overall population or among those on long-term opioid therapy. However, cannabis was associated with a small increased risk of composite adverse outcomes (ED visits, hospitalization, death). Among adults 65 and older on LTOT, cannabis use was associated with a 55% increased 90-day mortality risk (HR 1.55).

Why it matters

Cannabis has been proposed as an opioid-sparing therapy that could reduce opioid-related deaths. This large VA study found no such mortality benefit and identified increased risk in the oldest patients, challenging the opioid-sparing narrative.

The numbers in context

297,620 veterans. 30,514 cannabis users. Overall mortality HR: 1.07 (90-day, NS), 1.00 (180-day, NS). Composite outcome HR: 1.05 (90-day), 1.04 (180-day). Adults 65+ on LTOT: 90-day mortality HR 1.55 (95% CI 1.17-2.04).

How the study worked

Cohort study of 297,620 veterans with urine drug screening (2014-2019) who received opioid prescriptions through the VA system. Propensity score weighting reduced confounding. Cox regression estimated hazard ratios for 90- and 180-day outcomes.

What this study cannot tell us

Observational study cannot establish causation. Urine drug screening captures any recent use, not dose or frequency. Veterans may not represent the general population. Cannot distinguish therapeutic from recreational cannabis use.

How to read the evidence

Large VA cohort with propensity score adjustment and biologically verified cannabis exposure, published in JAMA Network Open.

When this study was published

Published in 2022, covering 2014-2019.

The bigger picture

The absence of a mortality benefit undermines one of the key arguments for cannabis as an opioid adjunct. The finding of increased risk in older adults on long-term opioids is particularly concerning given this is a rapidly growing demographic of cannabis users.

Questions still open

Why are older adults on long-term opioids at higher mortality risk with cannabis? Could drug interactions between cannabis and opioids explain the increased risk in seniors?

Common questions

Does cannabis reduce the risk of opioid overdose death?

This study of nearly 300,000 veterans on opioids found no reduction in mortality associated with cannabis use. In adults over 65 on long-term opioids, cannabis was actually associated with increased mortality.

Is it safe to use cannabis while taking opioids?

While cannabis did not increase mortality for most opioid users in this study, it was associated with a small increase in ER visits and hospitalizations, and a 55% increase in 90-day mortality among adults 65 and older on long-term opioid therapy.

Read the original research

Association of a Positive Drug Screening for Cannabis With Mortality and Hospital Visits Among Veterans Affairs Enrollees Prescribed Opioids.

JAMA network open, 5(12), e2247201

View on PubMed ↗Publisher’s paper ↗

Citation

Keyhani, Salomeh; Leonard, Samuel; Byers, Amy L; Zaman, Tauheed; Krebs, Erin; Austin, Peter C; Moss-Vazquez, Tristan; Austin, Charles; Sandbrink, Friedhelm; Bravata, Dawn M. (2022). Association of a Positive Drug Screening for Cannabis With Mortality and Hospital Visits Among Veterans Affairs Enrollees Prescribed Opioids.. JAMA network open, 5(12), e2247201. https://doi.org/10.1001/jamanetworkopen.2022.47201