Impact of patient and public involvement on enrolment and retention in clinical trials: systematic review and meta-analysis

Abstract

ObjectiveTo investigate the impact of patient and public involvement (PPI) on rates of enrolment and retention in clinical trials and explore how this varies with the context and nature of PPI.DesignSystematic review and meta-analysis.Data sourcesTen electronic databases, including Medline, INVOLVE Evidence Library, and clinical trial registries.Eligibility criteriaExperimental and observational studies quantitatively evaluating the impact of a PPI intervention, compared with no intervention or non-PPI intervention(s), on participant enrolment and/or retention rates in a clinical trial or trials. PPI interventions could include additional non-PPI components inseparable from the PPI (for example, other stakeholder involvement).Data extraction and analysisTwo independent reviewers extracted data on enrolment and retention rates, as well as on the context and characteristics of PPI intervention, and assessed risk of bias. Random effects meta-analyses were used to determine the average effect of PPI interventions on enrolment and retention in clinical trials: main analysis including randomised studies only, secondary analysis adding non-randomised studies, and several exploratory subgroup and sensitivity analyses.Results26 studies were included in the review; 19 were eligible for enrolment meta-analysis and five for retention meta-analysis. Various PPI interventions were identified with different degrees of involvement, different numbers and types of people involved, and input at different stages of the trial process. On average, PPI interventions modestly but significantly increased the odds of participant enrolment in the main analysis (odds ratio 1.16, 95% confidence interval and prediction interval 1.01 to 1.34). Non-PPI components of interventions may have contributed to this effect. In exploratory subgroup analyses, the involvement of people with lived experience of the condition under study was significantly associated with improved enrolment (odds ratio 3.14 v 1.07; P=0.02). The findings for retention were inconclusive owing to the paucity of eligible studies (odds ratio 1.16, 95% confidence interval 0.33 to 4.14), for main analysis).ConclusionsThese findings add weight to the case for PPI in clinical trials by indicating that it is likely to improve enrolment of participants, especially if it includes people with lived experience of the health condition under study. Further research is needed to assess which types of PPI work best in particular contexts, the cost effectiveness of PPI, the impact of PPI at earlier stages of trial design, and the impact of PPI interventions specifically targeting retention.Systematic review registrationPROSPERO CRD42016043808.

Frameworks for supporting patient and public involvement in research: Systematic review and co‐design pilot

“…The second, which some have described as consequentialist or efficiency‐oriented, is that patient and public involvement, by bringing a real‐world and lived‐experience perspective, improves the efficiency and value of research via a number of mechanisms: increasing its relevance to patients; improving recruitment and retention rates of research participants; extending the range of people represented in research studies; and improving dissemination of findings beyond academic audiences—though the evidence base for all these claims has been questioned …”

“About sixty per cent I want to do it”: Health researchers’ attitudes to, and experiences of, patient and public involvement (PPI)—A qualitative interview study

“…The UK's Chief Medical Officer has asserted that PPI can make “research more effective, more credible and often more cost efficient.” One systematic review found evidence of increased recruitment and retention, as well as some evidence that patient involvement helped in securing funding, in designing study protocols and in selecting relevant outcomes. A systematic review specifically on recruitment and retention found that PPI interventions had a modest but significant effect . In primary care, Blackburn et al found most reported impact was on the design of studies and writing participant information, with few reported impacts on gaining funding or on the management and conduct of research.…”

Evaluating patient and public involvement in research

“…The recent systematic review by Cocker and colleagues focusing on PPI’s effect on enrolment and retention in clinical trials (doi:10.1136/bmj.k4738)10 is an important addition. Their review suggests that PPI can improve rates of enrolment in clinical trials, thus bringing the most robust evidence to an association that has long been hypothesised 8.…”