The study summarized in this release relied on questionnaires about pain and quality of life in 901 people over age 65 who have used medical marijuana for 6 months for a variety of conditions (about two-thirds for either nonspecific or cancer-related pain).
The news release uses unjustified language and relative numbers to suggest the study shows that medical marijuana is “safe and efficacious” for a variety of conditions which afflict the elderly. But it doesn’t point out major limitations and significant conflicts of interest to the reader. Furthermore, the misleading headline implies that marijuana is safer and more effective than opioids (even though this was not part of the study). Finally, the last paragraph provocatively hints that marijuana might help reduce opioid dependence. This is purely speculative.
The treatment of chronic pain has been in the news a lot because of concerns about the inappropriate use of opioid medications that have led to dependence, abuse and overdoses. Side effects of opioids and most medicines are greater in older patients, so safer therapies would be welcome. Medical marijuana is one option that has gained increasing attention as jurisdictions in the US and elsewhere permit its use with a prescription from an authorized clinician. However, there is very limited evidence that medical marijuana is either safe or effective for most indications that it is currently being used for.
Most evidence focuses on patients with cancer and chemotherapy related side effects, but even here the evidence is inconclusive in that there are few head-to-head comparisons between medical marijuana and other active therapies.
As pointed out in the study: “the number of people aged 60 and over is expected to double by 2025 worldwide, and by 2050 in the United States.”
When you couple that statistic with the challenge of managing pain in the elderly then you can see how finding new approaches to pain is not just a pressing medical concern, but also a potentially lucrative business opportunity.
Most studies looking at the safety and efficacy of medical marijuana are — like this one — observational in nature. Therefore, they can only make statements regarding association and not causality. Another challenge to be aware of when reading about these studies is that of dosing. Because of the wide range of marijuana strains, and the variety of delivery options used, it’s very hard to accurately determine dosing.
Cost is not mentioned in this news release. The study involves several different methods of taking cannabis (smoking, infused oils, vaporization) which all involve a wide range of pricing. Moreover, it isn’t clear whether insurance pays for this or whether it represents out-of-pocket payments by patients.
The study abstract provides numerical data: “After six months of treatment, 93.7% of the respondents reported improvement in their condition and the reported pain level was reduced from a median of 8 on a scale of 0–10 to a median of 4.” However, the release got it wrong, saying that, “more than 93 percent of 901 respondents reported their pain dropped from a median of eight to four on a 10-point scale.” That isn’t the case. The release mixed it up.
In addition, the news release provides positive outcomes in pain control and quality of life using relative percentages, not absolute numbers. Further, the results are based on self-reporting in questionnaires, which are highly subjective and notoriously unreliable. Only about 900 (33%) of the original 2,736 subjects actually completed the study, and their follow-up was quite short at six months.
The news release mentions the “most commonly reported side effects were dizziness (9.7%) and dry mouth (7.1%).”
It would have been useful to include this information from the study: Among the roughly 900 subjects who took the follow-up questionnaire at six months, almost one-third “reported at least one adverse event.” For about 10 percent of these subjects, they reported this adverse event as a 7 out of 10 on the severity scale.
Quality of life was measured by a questionnaire that gave subjects 5 options (very good, good, neutral, bad, very bad).
Pain intensity was measured by the classic 11-point scale (0=no pain; 10= worst pain imaginable)
Perception of the general effects of cannabis was measure along 7 choices ranging from significant improvement all the way down to significant deterioration.
But the reproducibility of the findings from the questionnaires is very limited by small sample size (n= 901), the highly subjective nature of self-reporting, and the inability of the researchers to calculate dosing of the active substance (in this case, the THC in marijuana).
The study did not compare cannabis treatment to other therapies. Thus, the reported outcomes are not really comparative. Second, the study population had to be on cannabis for at least 6 months. But we don’t know about the effect in the majority of patients who took it for shorter periods. In effect, the release reports on pre-selected patients who are likely to have done well on the treatment.
None of these limitations were mentioned in the news release.
To its credit, the release does note at the end that the study should be followed up and “more evidence-based data from this special, aging population is imperative.”
No disease mongering in this news release.
Although the news release mentions that the subjects surveyed “received medical cannabis through ‘Tikun Olam,’ the largest Israeli medical cannabis supplier,” it does not point out the following:
This is definitely something readers should know in a news release that implies efficacy in treating nearly a dozen different conditions in the first two paragraphs. It’s quite clear that people over 65 represent a growing target market for medical cannabis.
There are a large number of treatment options for patients with pain due to various conditions but none are mentioned here except for the misleading assertion in the headline that cannabis was compared with opioids. As mentioned earlier, the release doesn’t acknowledge that there was no comparison to other therapies in this observational study. Rather, the release tends to dismiss them in terms of side effects using opioids as an example. There are other medicinal and non-medicinal therapies that could be used.
The news release does not address which countries (other than Israel) or US states have legalized medical marijuana. Availability depends very much on where the patient lives.
There have been several other studies looking at the safety and efficacy of using medical cannabis in the elderly. A 2014 review of them concluded:
“Adequately powered trials are needed to assess the efficacy and safety of cannabinoids in older subjects, as the potential symptomatic benefit is especially attractive in this age group.”
These other studies are not mentioned in the news release.
The title of the release, “Medical cannabis significantly safer for elderly with chronic pain than opioids,” goes far beyond what the study found. It implies this was a comparative study.
It’s overreaching to imply that cannabis is “safe and efficacious” in treating nearly a dozen conditions based solely on the self-reporting of a small number of subjects, and in an observational study that can not establish cause and effect.