Dr. Alhamad et al describe the outcomes after kidney transplantation in patients with cannabis dependence or abuse (CDOA).1 CDOA occurs infrequently before and after kidney transplantation when compared with the general population. The authors linked SRTR data with Medicare data, a clever way to get at CDOA in transplant patients. However, when comparing the timeframe of the study (2007–2015) with UNOS data,2 the total number of kidney transplants done in those years was 152 070—thus, this article evaluates roughly one-third (52 689) of all transplant recipients. It is probable that patients on Medicare pre-and posttransplant are different from those with private insurance, which puts the results in perspective.
The definition of CDOA was rather strict in that administrative billing data were used. Coders were only able to use CDOA as a diagnosis in patients who had an official diagnosis of dependence or abuse by a physician. Therefore, this article may underestimate CDOA. Some patients may successfully hide their habit, as not all transplant centers perform routine drug screening. This raises an interesting issue of fairness in access to transplantation: Should all centers screen transplant recipients the same way? This would limit autonomy of transplant centers but may improve fair access to kidney transplantation. CDOA patients mentioned in this article likely represent ‘extreme’ users of cannabis that in one way or another raised the suspicion of their healthcare providers. Thus, data from CDOA cannot be generalized to ‘social’ marijuana users in whom cannabis use does not have any adverse effects on life. Recreational, or ‘social’ marijuana use in otherwise normally functioning patients does not seem to adversely affect transplant outcomes,3 but larger studies on this subject are needed.
Pretransplant CDOA was more likely identified in young, thin, not-college educated, unemployed male patients of color. As the transplant community, we must face these results with brave honesty: first, with faithful reporting of results, and second, with ourselves. The latter forces us to face and mitigate our own stereotypes and biases that are firmly engrained and often unconscious. The association of CDOA with a certain demographic may contribute to unintentional stereotyping and increased scrutiny of transplant candidates that fit this demographic—a group of people who already suffer from other stereotypes and biases. This may further disadvantage an already disadvantaged minority in trying to gain access to transplantation. As the authors suggest, infusing additional resources to help CDOA patients become transplant candidates is a better strategy than denying them transplant candidacy outright, but one that demands a very dedicated team approach and significantly increases workload on the coordinators and social workers. At transplant evaluation, the goal should be to identify obstacles to transplantation and then to assist patients in overcoming these barriers, so they can ultimately enjoy the quality of life a transplant offers.
Pretransplant CDOA did not associate with worse posttransplant outcomes, but was associated with a host of posttransplant psychiatric complications. Given the careful pretransplant screening by multidisciplinary teams, it was shocking to find that patients with known CDOA were transplanted. In my experience, most transplant centers consider dependence or abuse of any substance an (absolute) contraindication to transplantation.
CDOA was also associated with COPD, diabetes mellitus, or long duration of pretransplant dialysis (>60 months). These diseases have symptoms such as shortness of breath, anxiety, nausea, vomiting, anorexia, which may be relieved by cannabinoids—thus this finding seems reasonable. It also raises the question whether CDOA started with recreational use or as a self-medication strategy when traditional medicine failed in these patients.
Importantly, CDOA pretransplant was frequently associated with other drug abuse (almost 35%), and depression (19%) in the first year posttransplant. Noncompliance (6.5%) and alcohol abuse (4%) were also common. In multivariate analysis, alcohol and other drug use, as well as noncompliance, among other issues, were still more common posttransplant in CDOA patients. Therefore, CDOA pretransplant must be taken seriously, and patients with CDOA should require a thorough social work and psychiatric evaluation pretransplant, with dedicated screening for other substance use or abuse, depression, and noncompliance. Pretransplant CDOA patients may benefit from additional follow-up posttransplant to mitigate these issues.
Posttransplant CDOA was associated with worse outcomes than pretransplant CDOA: namely, death-censored and all-cause graft failure, other drug abuse, noncompliance, hypotension, even death (on univariate analysis only). The combination of CDOA with other drug abuse and/or seems especially dangerous. This is corroborated by at least one other report, in which tobacco use alone or combined with marijuana use led to worse outcomes, but marijuana use alone did not.4 Furthermore, the article describes a significant amount of ‘new’ CDOA posttransplant in patients without a pretransplant CDOA history. This may indicate some missed diagnoses pretransplant, and some truly new CDOA. Not surprisingly, CDOA patients did have more accidents, motor vehicle crashes, and fractures. It is hard to know whether these were all clearly cannabis-related owing to the significant overlap with other substance use in over one-third of posttransplant CDOA patients.
In summary, patients with CDOA comprise a subgroup of all patients with cannabis use. Recreational cannabis use, or self-medication, may not alter posttransplant outcomes when cannabis use does not negatively impact patients’ lives. Thus, cannabis use in and of itself is not necessarily an absolute contraindication to kidney transplantation. However, all cannabis users should undergo careful screening for any substance dependence or abuse and associated comorbidities (such as depression or noncompliance). Given the poorer outcomes in CDOA patients, it seems reasonable to address CDOA before transplantation. Access to and participation in treatment programs before and maybe even after transplantation should be facilitated when possible to maximize the benefit of transplantation. Whether a universal policy or guideline on screening transplant candidates for substance use, dependence, or abuse should be developed to provide fair access to transplantation for all candidates across the country remains an open question.
The author thanks Mr. Cory Anderson for careful review of this article.
1. Alhamad T, Koraishy FM, Lam NN, et al. Cannabis dependence or abuse in kidney transplantation: implications for posttransplant outcomes.Transplantation20191032373–2382
3. Greenan G, Ahmad SB, Anders MG, et al. Recreational marijuana use is not associated with worse outcomes after renal transplantation.Clin Transplant201630101340–1346
4. Fabbri K, Anderson-Haag T, Spenningsby A, et al. Marijuana use should not preclude consideration for kidney transplantation. [abstract].Am J Transplant201717Suppl 3