O'Keefe Daniel, Scott Nick, Aitken Campbell, Dietze Paul
Behaviours and Health Risks, Burnet Institute, 85 Commercial Rd, Melbourne, VIC, 3004, Australia; School of Public Health and Preventive Medicine, Monash University, 99 Commercial Rd, Melbourne, VIC, 3004, Australia.
Drug Alcohol Depend. 2017 Jul 1;176:7-13. doi: 10.1016/j.drugalcdep.2017.02.013. Epub 2017 Apr 13.
Needle and syringe program (NSP) coverage is often calculated at the individual level. This method relates sterile needle and syringe acquisition to injecting frequency, resulting in a percentage of injecting episodes that utilise a sterile syringe. Most previous research using this method was restricted by their cross-sectional design, calling for longitudinal exploration of coverage.
We used the data of 518 participants from an ongoing cohort of people who inject drugs in Melbourne, Australia. We calculated individual-level syringe coverage for the two weeks prior to each interview, then dichotomised the outcome as either "sufficient" (≥100% of injecting episodes covered by at least one reported sterile syringe) or "insufficient" (<100%). Time-variant predictors of change in recent coverage (from sufficient to insufficient coverage) were estimated longitudinally using logistic regression with fixed effects for each participant.
Transitioning to methamphetamine injection (AOR:2.16, p=0.004) and a newly positive HCV RNA test result (AOR:4.93, p=0.001) were both associated with increased odds of change to insufficient coverage, whilst change to utilising NSPs as the primary source of syringe acquisition (AOR: 0.41, p=0.003) and opioid substitution therapy (OST) enrolment (AOR:0.51, p=0.013) were protective against a change to insufficient coverage.
We statistically tested the transitions between time-variant exposure sub-groups and transitions in individual-level syringe coverage. Our results give important insights into means of improving coverage at the individual level, suggesting that methamphetamine injectors should be targeted, whilst both OST prescription and NSP should be expanded.
针头和注射器项目（NSP）的覆盖率通常在个体层面进行计算。这种方法将无菌针头和注射器的获取与注射频率联系起来，得出使用无菌注射器的注射次数的百分比。以往大多数使用这种方法的研究都受到其横断面设计的限制，因此需要对覆盖率进行纵向探索。
我们使用了来自澳大利亚墨尔本一个正在进行的注射吸毒者队列研究中518名参与者的数据。我们计算了每次访谈前两周的个体层面注射器覆盖率，然后将结果分为“充足”（至少一支报告的无菌注射器覆盖≥100%的注射次数）或“不足”（<100%）。使用固定效应逻辑回归对每位参与者纵向估计近期覆盖率变化（从充足到不足）的时变预测因素。
转为注射甲基苯丙胺（比值比：2.16，p=0.004）和新的丙型肝炎病毒RNA检测结果呈阳性（比值比：4.93，p=0.001）均与覆盖率变为不足的几率增加相关，而转为将NSP作为注射器获取的主要来源（比值比：0.41，p=0.003）和加入阿片类药物替代疗法（OST）（比值比：0.51，p=0.013）对覆盖率变为不足具有保护作用。
我们对时变暴露亚组之间的转变以及个体层面注射器覆盖率的转变进行了统计学检验。我们的结果为提高个体层面覆盖率的方法提供了重要见解，表明应针对注射甲基苯丙胺者，同时应扩大OST处方和NSP。
