People on liver transplant waitlist may be no worse off if they have used marijuana

Last Updated: 2018-02-08

By Lorraine L. Janeczko

NEW YORK (Reuters Health) - Candidates on the liver transplant (LT) waitlist who have used marijuana have no worse outcomes than their counterparts on the list who have not used it, a single-center study suggests.

"Unlike illicit drug use, marijuana use was not associated with worse outcomes on the LT waitlist. . . . We found a high prevalence of historical marijuana use that did not have clear adverse effects on LT waitlist outcomes," lead author Prashant Kotwani of the University of California San Francisco School of Medicine and colleagues write in Transplantation, online January 10.

The research team retrospectively analyzed data from adults evaluated for LT from January 2012 through December 2013 at the UCSF LT center. A history of marijuana use was determined through self-reports, urine tests or both. The LT program did not permit patients with ongoing marijuana use to be listed.

Of the 884 evaluated adults (mean age, 58), the 585 (66%) who were listed for LT had a median follow-up of 1.4 years. Of the 585 listed patients, 5% had recently used marijuana, 40% had used it previously, and 55% had never used it.

Marijuana use was significantly associated with hepatitis C infection (incidence rate ratio, 2.1, compared with hepB infection) and with prior (IRR, 1.4) and recent (IRR, 1.3) tobacco use. Marijuana users also were less likely to never have used alcohol and more likely to have used it heavily or abused it (compared with social alcohol use), as well as more likely to have previously or recently used illicit drugs.

In adjusted analyses, marijuana use was not linked with likelihood of LT, waitlist mortality, or de-listing. Recent illicit drug use, however, was linked with a significantly higher risk of death or de-listing (hazard ratio, 1.8).

The authors call for interpreting these results with caution and for additional related research.

Dr. David Klassen, the chief medical officer of United Network for Organ Sharing in Richmond, Virginia, told Reuters Health by phone, "Legal marijuana use is growing, and certainly many transplant patients have that in their background. Given the changing attitudes toward marijuana and the widespread use of it, this issue is currently being reassessed by a lot of transplant programs."

"While I was not surprised by the lack of any effect of prior marijuana use on liver transplant outcomes following listing, I was surprised by the large number of patients who reported prior marijuana use," noted Dr. Klassen, who was not involved in the study.

"The results of this study will potentially broaden access to transplantation," he said. "It will be useful to broaden the conversation about who is an appropriate transplant candidate and who is not - and the reasons why a patient can be accepted or denied listing for transplantation."

Dr. Klassen would like to see the results replicated before applying them broadly.

Dr. Willscott E. Naugler, the medical director of Liver Transplantation and of the Multidisciplinary Liver Tumor Group at Oregon Health & Sciences University in Portland, told Reuters Health by email, "Patients with substance abuse problems, including alcohol, opiates, etc., do well if they stop before transplant and change to an abstinence-oriented life. Most patients who have used or who currently use marijuana do not have substance abuse problems, and those who have those problems are usually eliminated by policies that prohibit use in order to get transplanted."

"Many patients find that marijuana use helps them clinically, for example with chronic pain syndromes where they might otherwise be on chronic high-dose narcotics," added Dr. Naugler, who also was not involved in the study. "In this and other conditions, marijuana may have fewer side effects than other treatments, and patients in need of liver transplant thus may be considered even in the context of ongoing marijuana use."

"The next dataset the liver transplant community needs to gather is how patients do using marijuana while on the waitlist and after transplant," Dr. Naugler added. "We need to understand if prudent marijuana usage leads to adverse outcomes (such as more complications of liver disease on the waitlist or more problems after transplant, including rejection and death)."

Dr. Kotwani did not respond to requests for comment.

SOURCE: http://bit.ly/2nzkiSW

Transplantation 2018.