加拿大不列颠哥伦比亚疾病控制中心Jane A Buxton团队研究了非癌症疼痛的处方阿片类药物治疗和开始静脉注射毒品的相关性。相关论文于2021年11月18日发表于《英国医学杂志》上。

为了评估长期处方阿片类药物治疗非癌症疼痛与无毒品使用史个体初始静脉注射吸毒（IDU）之间的相关性，研究组进行了一项回顾性队列研究。他们利用大型行政数据源（包含加拿大不列颠哥伦比亚省约170万人的丙型肝炎病毒或艾滋病毒检测信息），与行政健康数据库链接（包括社区药房的处方）。

根据2000-2015年间分配的药物，研究组确定了非癌症疼痛处方类阿片的使用次数。发作按阿片类药物使用的持续时间和强度进行分类，即急性（持续时间<90天）、发作性（持续时间）≥90天发作，药物供应<90天和/或发作强度<50%；以及慢性（持久性）≥90天，药品供应≥90天和/或发作强度≥50%。

在社会经济变量方面，有慢性发作的人与那些有偶发性或急性发作的人以及那些阿片类药物初用的人进行了1:1 1:1的匹配。初始IDU由一个经过验证的具有高度特异性的管理算法确定。通过治疗权重的逆概率加权的Cox模型评估了阿片类药物使用类别（慢性、偶发、急性、阿片类药物初用）与初始IDU之间的关联。

59804名参与者（每个阿片类药物使用类别14951人）被纳入匹配队列，中位随访5.8年。1149名参与者发生IDU。慢性阿片类药物使用的参与者在5年内开始IDU的累积概率最高（4.0%），其次是偶发性使用（1.3%）和急性使用（0.7%），阿片类药物初用的概率最小（0.4%）。

在逆概率治疗加权Cox模型中，慢性阿片类药物使用组的初始IDU风险比未使用阿片类药物组高8.4倍。在一项仅限于有慢性疼痛史的个体的敏感性分析中，长期使用者的累积风险（5年内为3.4%）低于主要结局，但相对风险不低于主要结局，危险比为9.7。阿片类药物剂量越高，患者年龄越小，初始IDU的概率越高。

研究结果表明，接受慢性处方阿片类药物治疗的非癌性疼痛患者的IDU开始率总体上不高（5年内为3-4%），但大约是未接受阿片类药物治疗的患者的8倍。

附：英文原文

Title: Prescription opioid treatment for non-cancer pain and initiation of injection drug use: large retrospective cohort study

Author: James Wilton, Younathan Abdia, Mei Chong, Mohammad Ehsanul Karim, Stanley Wong, Aaron MacInnes, Rob Balshaw, Bin Zhao, Tara Gomes, Amanda Yu, Maria Alvarez, Richard C Dart, Mel Krajden, Jane A Buxton, Naveed Z Janjua, Roy Purssell

Issue&Volume: 2021/11/18

Abstract:

Objective To assess the association between long term prescription opioid treatment medically dispensed for non-cancer pain and the initiation of injection drug use (IDU) among individuals without a history of substance use.

Design Retrospective cohort study.

Setting Large administrative data source (containing information for about 1.7 million individuals tested for hepatitis C virus or HIV in British Columbia, Canada) with linkage to administrative health databases, including dispensations from community pharmacies.

Participants Individuals age 11-65 years and without a history of substance use (except alcohol) at baseline.

Main outcome measures Episodes of prescription opioid use for non-cancer pain were identified based on drugs dispensed between 2000 and 2015. Episodes were classified by the increasing length and intensity of opioid use (acute (lasting <90 episode days), episodic (lasting ≥90 episode days; with <90 days’ drug supply and/or <50% episode intensity), and chronic (lasting ≥90 episode days; with ≥90 days’ drug supply and ≥50% episode intensity)). People with a chronic episode were matched 1:1:1:1 on socioeconomic variables to those with episodic or acute episodes and to those who were opioid naive. IDU initiation was identified by a validated administrative algorithm with high specificity. Cox models weighted by inverse probability of treatment weights assessed the association between opioid use category (chronic, episodic, acute, opioid naive) and IDU initiation.

Results 59804 participants (14951 people from each opioid use category) were included in the matched cohort, and followed for a median of 5.8 years. 1149 participants initiated IDU. Cumulative probability of IDU initiation at five years was highest for participants with chronic opioid use (4.0%), followed by those with episodic use (1.3%) and acute use (0.7%), and those who were opioid naive (0.4%). In the inverse probability of treatment weighted Cox model, risk of IDU initiation was 8.4 times higher for those with chronic opioid use versus those who were opioid naive (95% confidence interval 6.4 to 10.9). In a sensitivity analysis limited to individuals with a history of chronic pain, cumulative risk for those with chronic use (3.4% within five years) was lower than the primary results, but the relative risk was not (hazard ratio 9.7 (95% confidence interval 6.5 to 14.5)). IDU initiation was more frequent at higher opioid doses and younger ages.

Conclusions The rate of IDU initiation among individuals who received chronic prescription opioid treatment for non-cancer pain was infrequent overall (3-4% within five years) but about eight times higher than among opioid naive individuals. These findings could have implications for strategies to prevent IDU initiation, but should not be used as a reason to support involuntary tapering or discontinuation of long term prescription opioid treatment.

DOI: 10.1136/bmj-2021-066965

Source: https://www.bmj.com/content/375/bmj-2021-066965