Research Centre, Centre Hospitalier de l'Université de Montréal, Montréal, Canada.
Department of Social and Preventive Medicine, School of Public Health, Université de Montréal, Montréal, Canada.
Addiction. 2021 Mar;116(3):571-582. doi: 10.1111/add.15192. Epub 2020 Aug 16.
Disbursement of income assistance has been temporally associated with intensified drug use and related harms (coined the 'cheque effect'). However, relationships to injection drug use (IDU) remain understudied. We examined short-term 'cheque effects' and associated factors among people who inject drugs (PWID).
Cross-sectional analysis nested within a cohort study.
Montreal, Quebec, Canada.
PWID receiving income assistance, with no employment income. A total of 613 PWID (median age 41, 83% male) contributed 3269 observations from 2011 to 2017.
At each cohort visit, an interviewer-administered questionnaire captured retrospective reports of injection-related behaviour during the 2-day periods (i) before and (ii) including/after receiving last month's income assistance payment (number of injections; drugs injected; any receptive syringe-sharing). The relative likelihood (odds) and magnitude (rate) of an increase in injection frequency ('cheque effect') were estimated in relation to social and behavioural factors using logistic and negative binomial regression in a covariate-adjusted two-part model.
Prevalence of IDU and syringe-sharing were, respectively, 1.80 and 2.50 times higher in the days following versus preceding cheque receipt (P < 0.001). Among people with past-month IDU, most observations showed increased injection frequency (52%) or no change in injection frequency (44%). The likelihood of a 'cheque effect' was positively associated with cocaine injection [versus injection of other substances, odds ratio (OR) = 2.639, 95% confidence interval (CI) = 2.04-3.41], unstable housing (OR = 1.272, 95% CI = 1.03-1.57) and receiving opioid agonist therapy (OR =1.597, 95% CI = 1.27-2.00) during the same month. Magnitude of the 'cheque effect' was positively associated with cocaine injection [rate ratio (RR) = 1.795, 95% CI = 1.43-2.16], unstable housing (RR = 1.198, 95% CI = 1.02-1.38) and frequent injection (RR = 2.938, 95% CI = 2.43-3.44), but inversely associated with opioid agonist therapy (RR = 0.817, 95% CI = 0.68-0.95) and prescription opioid injection (RR = 0.794, 95% CI = 0.66-0.93).
Among people who inject drugs in Montreal, Canada, injection drug use and receptive syringe-sharing appear to be more prevalent in the 2 days after versus before receiving income assistance. The odds and rate of individual-level increases in injection frequency appear to be positively associated with cocaine injection (versus injection of other substances) and unstable housing.
收入援助的发放与毒品使用的加剧和相关危害（称为“支票效应”）在时间上有关联。然而，与注射吸毒（IDU）的关系仍在研究中。我们研究了接受收入援助的吸毒者（PWID）中短期的“支票效应”及其相关因素。
嵌套在队列研究中的横断面分析。
加拿大魁北克省蒙特利尔市。
接受收入援助且没有就业收入的吸毒者。共有 613 名吸毒者（中位年龄 41 岁，83%为男性）在 2011 年至 2017 年间贡献了 3269 次观察。
在每次队列访视时，通过访谈者管理的问卷，收集了参与者在过去 2 天内的注射相关行为的回顾性报告（i）在收到上月收入援助金之前和（ii）包括/在收到上月收入援助金之后。使用逻辑回归和负二项回归，在协变量调整的两部分模型中，根据社会和行为因素，估计了注射频率增加的相对可能性（优势比（OR））和幅度（率）（注射频率增加）。
与收到支票前相比，收到支票后 IDU 和注射器共享的发生率分别高 1.80 倍和 2.50 倍（P<0.001）。在过去一个月有 IDU 的人群中，大多数观察结果显示注射频率增加（52%）或注射频率无变化（44%）。“支票效应”的可能性与可卡因注射呈正相关（与注射其他物质相比，OR=2.639，95%置信区间（CI）=2.04-3.41），与不稳定住房（OR=1.272，95%CI=1.03-1.57）和同期接受阿片类激动剂治疗（OR=1.597，95%CI=1.27-2.00）有关。“支票效应”的幅度与可卡因注射呈正相关（RR=1.795，95%CI=1.43-2.16），与不稳定住房（RR=1.198，95%CI=1.02-1.38）和频繁注射（RR=2.938，95%CI=2.43-3.44）有关，但与阿片类激动剂治疗（RR=0.817，95%CI=0.68-0.95）和处方类阿片类药物注射（RR=0.794，95%CI=0.66-0.93）呈负相关。
在加拿大蒙特利尔的吸毒者中，接受收入援助后，注射吸毒和接受性注射器共享的情况似乎在收到援助后的前两天更为普遍。个体注射频率增加的可能性和幅度似乎与可卡因注射（与注射其他物质相比）和不稳定住房呈正相关。
