National Drug and Alcohol Research Centre, University of New South Wales Sydney, Sydney, NSW, Australia.
Centre for Youth Substance Abuse Research, University of Queensland, Brisbane, QLD, Australia; National Addiction Centre, Kings College London, London, UK.
Lancet Public Health. 2018 Jul;3(7):e341-e350. doi: 10.1016/S2468-2667(18)30110-5.
Interest in the use of cannabis and cannabinoids to treat chronic non-cancer pain is increasing, because of their potential to reduce opioid dose requirements. We aimed to investigate cannabis use in people living with chronic non-cancer pain who had been prescribed opioids, including their reasons for use and perceived effectiveness of cannabis; associations between amount of cannabis use and pain, mental health, and opioid use; the effect of cannabis use on pain severity and interference over time; and potential opioid-sparing effects of cannabis.
The Pain and Opioids IN Treatment study is a prospective, national, observational cohort of people with chronic non-cancer pain prescribed opioids. Participants were recruited through community pharmacies across Australia, completed baseline interviews, and were followed up with phone interviews or self-complete questionnaires yearly for 4 years. Recruitment took place from August 13, 2012, to April 8, 2014. Participants were asked about lifetime and past year chronic pain conditions, duration of chronic non-cancer pain, pain self-efficacy, whether pain was neuropathic, lifetime and past 12-month cannabis use, number of days cannabis was used in the past month, and current depression and generalised anxiety disorder. We also estimated daily oral morphine equivalent doses of opioids. We used logistic regression to investigate cross-sectional associations with frequency of cannabis use, and lagged mixed-effects models to examine temporal associations between cannabis use and outcomes.
1514 participants completed the baseline interview and were included in the study from Aug 20, 2012, to April 14, 2014. Cannabis use was common, and by 4-year follow-up, 295 (24%) participants had used cannabis for pain. Interest in using cannabis for pain increased from 364 (33%) participants (at baseline) to 723 (60%) participants (at 4 years). At 4-year follow-up, compared with people with no cannabis use, we found that participants who used cannabis had a greater pain severity score (risk ratio 1·14, 95% CI 1·01-1·29, for less frequent cannabis use; and 1·17, 1·03-1·32, for daily or near-daily cannabis use), greater pain interference score (1·21, 1·09-1·35; and 1·14, 1·03-1·26), lower pain self-efficacy scores (0·97, 0·96-1·00; and 0·98, 0·96-1·00), and greater generalised anxiety disorder severity scores (1·07, 1·03-1·12; and 1·10, 1·06-1·15). We found no evidence of a temporal relationship between cannabis use and pain severity or pain interference, and no evidence that cannabis use reduced prescribed opioid use or increased rates of opioid discontinuation.
Cannabis use was common in people with chronic non-cancer pain who had been prescribed opioids, but we found no evidence that cannabis use improved patient outcomes. People who used cannabis had greater pain and lower self-efficacy in managing pain, and there was no evidence that cannabis use reduced pain severity or interference or exerted an opioid-sparing effect. As cannabis use for medicinal purposes increases globally, it is important that large well designed clinical trials, which include people with complex comorbidities, are conducted to determine the efficacy of cannabis for chronic non-cancer pain.
National Health and Medical Research Council and the Australian Government.
由于大麻素类药物具有减少阿片类药物剂量需求的潜力，因此人们对使用大麻和大麻素类药物治疗慢性非癌性疼痛的兴趣日益增加。本研究旨在调查正在使用阿片类药物治疗慢性非癌性疼痛的患者中使用大麻的情况，包括他们使用大麻的原因和对大麻有效性的看法；大麻使用量与疼痛、心理健康和阿片类药物使用之间的关系；大麻使用对疼痛严重程度和干扰的随时间变化的影响；以及大麻可能具有的节省阿片类药物的作用。
疼痛和阿片类药物治疗研究是一项前瞻性的、全国性的、观察性的慢性非癌性疼痛患者使用阿片类药物的队列研究。通过澳大利亚各地的社区药房招募参与者，他们完成了基线访谈，并在 4 年内每年通过电话访谈或自我完成问卷进行随访。招募工作于 2012 年 8 月 13 日至 2014 年 4 月 8 日进行。参与者被问及终生和过去一年的慢性疼痛状况、慢性非癌性疼痛的持续时间、疼痛自我效能感、疼痛是否为神经性、终生和过去 12 个月的大麻使用情况、过去一个月大麻使用的天数，以及目前的抑郁和广泛性焦虑症。我们还估计了阿片类药物的每日口服吗啡等效剂量。我们使用逻辑回归分析了大麻使用频率的横断面相关性，使用滞后混合效应模型检验了大麻使用与结局之间的时间相关性。
1514 名参与者完成了基线访谈，从 2012 年 8 月 20 日至 2014 年 4 月 14 日被纳入研究。大麻的使用很常见，到 4 年随访时，295 名（24%）参与者曾因疼痛使用过大麻。对使用大麻治疗疼痛的兴趣从基线时的 364 名（33%）参与者增加到 4 年时的 723 名（60%）参与者。在 4 年随访时，与不使用大麻的患者相比，我们发现使用大麻的患者疼痛严重程度评分更高（风险比 1.14，95%CI 1.01-1.29，使用频率较低；1.17，1.03-1.32，每日或接近每日使用），疼痛干扰评分更高（1.21，1.09-1.35；1.14，1.03-1.26），疼痛自我效能评分更低（0.97，0.96-1.00；0.98，0.96-1.00），广泛性焦虑症严重程度评分更高（1.07，1.03-1.12；1.10，1.06-1.15）。我们没有发现大麻使用与疼痛严重程度或疼痛干扰之间存在时间关系的证据，也没有发现大麻使用减少了处方阿片类药物的使用或增加了阿片类药物停药的发生率。
在接受阿片类药物治疗的慢性非癌性疼痛患者中，大麻的使用很常见，但我们没有发现大麻使用能改善患者结局的证据。使用大麻的患者疼痛更严重，自我管理疼痛的效能感更低，而且没有证据表明大麻使用减少了疼痛的严重程度或干扰，也没有证据表明大麻具有节省阿片类药物的作用。随着大麻作为药用目的在全球范围内的使用增加，开展包括患有复杂合并症患者在内的大型、精心设计的临床试验，以确定大麻治疗慢性非癌性疼痛的疗效非常重要。
澳大利亚国家卫生与医学研究理事会和澳大利亚政府。
