June 14, 2021
National Center for Health Research’s Public Comments Regarding AHRQ’s Draft Systematic Review on Cannabis and Other Plant-Based Treatments for Chronic Pain
We are writing to express our views on the Agency for Healthcare Research and Quality’s (AHRQ) draft systematic review on cannabis and other plant-based treatments for chronic pain.
The National Center for Health Research (NCHR) is a nonprofit think tank that conducts, analyzes, and scrutinizes research on a range of health issues, with particular focus on which prevention strategies and treatments are most effective for which patients and consumers. We do not accept funding from companies that make products that are the subject of our work, so we have no conflicts of interest.
Although we support the goals of the review and agree that there is a need for a systematic review of the effects of cannabis and other plant-based treatments for chronic pain, there are several important limitations of the report that were either not adequately addressed or were not mentioned.
For many of the limitations that were only briefly mentioned, the review fails to adequately address the substantial impact of those limitations on the interpretation of the findings. For example, the vast majority of trials included in the draft review were focused on patients with neuropathic chronic pain. There is very little evidence on other types of chronic pain, including low back pain, osteoarthritis, fibromyalgia, and inflammatory arthritis. If the goal of this report is, as stated, to “help health care decision makers—patients and clinicians, health system leaders, and policymakers, among others—make well-informed decisions and thereby improve the quality of healthcare services,” this exclusion of large groups of patients must be emphasized, explaining that the scope of the draft review is limited to a specific patient population. Otherwise, the results will be misleading to those who rely on the review to aid in their decision-making.
Further, study durations were short-term (many only 4-6 weeks long), and they included less than 6 months follow-up. However, those with chronic pain often seek long-term treatments that they will use for years. Short studies are not an adequate basis from which to draw conclusions about the long-term use of cannabinoids for chronic pain management. Although the limitation due to short-term studies is acknowledged in the review, it must be emphasized so that readers quickly skimming the review or only reading the section on conclusions are made aware of this limitation.
The fact that the products studied lack consistent nomenclature also represents a serious limitation. As the draft review states, several studies only describe products as “extracted” without giving additional information of the purity of the studied end product or as to how the product was extracted. Not only does this severely limit the interpretation of the evidence cited in this review, it also seriously hampers health care providers and patients ability to find information and choose the right treatments for them.
In addition, several limitations were not even mentioned in this report. For example, the draft report notes that the RCTs reviewed did not report on the impact that cannabinoid use had on opioid use. However, the draft does include observational studies of cannabinoid use, and there is a body of observational research on the relationship between cannabinoid and opioid use for chronic pain management.1 Since observational studies on cannabinoid use for pain management were deemed acceptable to include in the draft report, it is inconsistent that observational studies on the impact that cannabinoid use for chronic pain management has on opioid use for the same purpose were not selected for inclusion in the draft report. We urge that the draft report be revised in order to address this growing body of research.
As our final important point, the title of the draft report is misleading. The current title is “Living Systematic Review on Cannabis and Other Plant-Based Treatments for Chronic Pain.” However, the review has reported no research on other plant-based treatments such as kratom, nor does it report on high THC to CBD ratio products extracted from whole-plant cannabis, whole-plant cannabis products, or low THC to CBD ratio products such as topical CBD. The review is much more limited in scope, focusing on treatments such as comparable THC to CBD ratio oral spray. The title of the review should therefore reflect the narrow range of cannabinoid products covered by the review; otherwise, it is inaccurate and misleading to those who will turn to it for medical information and to aid in decision making.
References
1. Okusanya BO, Asaolu IO, Ehiri JE, Kimaru LJ, Okechukwu A, Rosales C. Medical cannabis for the reduction of opioid dosage in the treatment of non-cancer chronic pain: a systematic review. Systematic Reviews. 2020 Dec;9(1):1-8.