Needle exchange programs for the prevention of hepatitis C virus infection in people who inject drugs: a systematic review with meta-analysis

Abstract

BackgroundPrevious research on the effectiveness of needle exchange programs (NEP) in preventing hepatitis C virus (HCV) in people who inject drugs (PWID) has shown mixed findings. The purpose of this study was to use the meta-analytic approach to examine the association between NEP use and HCV prevention in PWIDs.MethodsStudy inclusion criteria were (1) observational studies, (2) PWIDs, (3) NEP use, (4) HCV status ascertained by serological testing, (5) studies published in any language since January 1, 1989, and (6) data available for measures of association. Studies were located by searching four electronic databases and cross-referencing. Study quality was assessed using the Newcastle Ottawa (NOS) scale. A ratio measure of association was calculated for each result from cohort or case–control studies and pooled using a random effects model. Odds ratio (OR) and hazard ratio (HR) models were analyzed separately. Results were considered statistically significant if the 95% confidence interval (CI) did not cross 1. Heterogeneity was estimated using Q and I 2 with alpha values for Q ≤ 0.10 considered statistically significant.ResultsOf the 555 citations reviewed, 6 studies containing 2437 participants were included. Studies had an average NOS score of 7 out of 9 (77.8%) stars. Concerns over participant representativeness, unclear adjustments for confounders, and bias from participant nonresponse and loss to follow-up were noted. Results were mixed with the odds ratio model indicating no consistent association (OR, 0.51, 95% CI, 0.05–5.15), and the hazard ratio model indicating a harmful effect (HR, 2.05, 95% CI, 1.39–3.03). Substantial heterogeneity (p ≤ 0.10) and moderate to large inconsistency (I 2 ≥ 66%) were observed for both models.ConclusionsThe impact of NEPs on HCV prevention in PWIDs remains unclear. There is a need for well-designed research studies employing standardized criteria and measurements to clarify this issue.Trial registrationPROSPERO CRD42016035315 Electronic supplementary materialThe online version of this article (doi:10.1186/s12954-017-0156-z) contains supplementary material, which is available to authorized users.

PRO: Needle Exchange Programs Should Be Instituted to Reduce Hepatitis C Virus Transmission†

“…It is important to remember that individual studies on this topic are retrospective in design because it would be an unethical violation of beneficence to randomize people away from the potentially beneficial intervention of NEPs. For this reason, they are frequently combined into meta‐analyses that show conflicting evidence on the impact of NEPs in reducing HCV transmission, particularly in North America . Many of the inconsistencies in the data can be explained by confounding, misclassification of the intervention exposure, and bias.…”

“…Confounding exists because of inadequate control for important covariables influencing HCV transmission, such as frequency of injection, duration and type of injection drug use, baseline injection risk behavior, homelessness, and high‐risk sexual practices. In one meta‐analysis, only half of the studies controlled for any confounders in their data . Misclassification of the intervention exposure has also been widespread, with many studies failing to standardize for the intervention of interest: high‐coverage NEPs.…”

“…Misclassification of the intervention exposure has also been widespread, with many studies failing to standardize for the intervention of interest: high‐coverage NEPs. For example, one meta‐analysis showed that NEPs have no effect or may even increase HCV transmission . Unfortunately, none of the included studies required high‐coverage NEPs (≥100% of injections covered by a clean syringe), and only one mandated weekly attendance.…”

Hepatitis C elimination – Macro‐elimination

“…NSP is recommended to reduce the spread of HIV and hepatitis in PWID . Certain reviews have concluded that there is evidence that NSP is reducing injection risk behaviour and transmission of HIV but the data are insufficient to confirm its effectiveness in preventing the transmission of HCV . On the other hand, there are studies showing that NSP prevents HCV transmission, in particular when it is combined with OAT .…”

“…16,[33][34][35] Certain reviews have concluded that there is evidence that NSP is reducing injection risk behaviour and transmission of HIV but the data are insufficient to confirm its effectiveness in preventing the transmission of HCV. [36][37][38] On the other hand, there are studies showing that NSP prevents HCV transmission, in particular when it is combined with OAT. 16,35 In a recent Cochrane report, Platt et al concluded that OAT was associated with a 50% reduction in the HCV transmission rate, while needle exchange programs (NEP) alone was less effective with a reduction of 21%.…”