Application of an adapted PRECIS-2 instrument to assess efficacy- and effectiveness-study designs in a systematic review of intervention studies of the hepatitis C virus-care continuum among people who use drugs

Abstract

Introduction: Systematic reviews and meta-analyses examining intervention studies may need to categorize studies by the degree to which they reflect efficacy or effectiveness study-design elements when reporting systematic reviews and meta-analysis results. Materials and methods: We identified reports presenting data from intervention studies eligible for evaluation with an adapted PRECIS-II instrument as part of a larger systematic review of the hepatitis C virus (HCV)-care continuum among people who used drugs. We applied the instrument to score reports examining any of the HCV-care-continuum steps of testing, linkage to care, and treatment on an efficacy-effectiveness spectrum. Composite scores are presented in tabular format and in stacked dot plots. Results: The adapted PRECIS-II instrument was applied to 37 unique reports that presented data on 51 HCV-care-continuum outcomes of testing (n=16), linkage to care (n=12), and treatment (n=23). Totals of 28, six, and three reports had been produced on one, two, or all three outcomes, respectively. Ten and eight studies described themselves as having efficacy or effectiveness designs, respectively; 33 did not specify. PRECIS-II composite scores for reports produced on testing, linkage to care, and treatment ranged widely: 1.22-5. Composite scores for reports examining HCV treatment indicated study designs that tended toward effectiveness (3.35), but those examining testing (3.85) or linkage (3.8) had more effectiveness-study designs (P=0.003, P=0.013, respectively). Conclusion: Reviewed reports varied widely in their use of efficacy/effectiveness-study designs, suggesting that systematic reviews and meta-analyses need to consider heterogeneity in efficacy/effectiveness study design in analyses. Most reports tended modestly toward having effectiveness designs, and treatment studies contained the most elements of efficacy-study designs. When assessing large numbers of reports with the PRECIS-II instrument, stacked dot plots may aid visually in depicting the range of scores. This review suggests that studies of the effectiveness of HCV treatment of people who use drugs at a population level is a research gap.