Objectives: The objectives were to provide an estimate of expected enrolment and attrition rates based on published studies of existing self-management interventions for people with multiple sclerosis, and to identify contributing factors and impact on outcomes.
Review methods: A systematic literature search was conducted using Ovid MEDLINE, PsychINFO, EMBASE, AMED, CINAHL, OT Seeker, PubMed, and the Cochrane Database of Systematic Reviews databases. Controlled trials with or without randomization using either a between-group or within-person design were included if they met specified criteria. A random-effect meta-regression analysis was conducted to estimate the overall enrolment and attrition proportions, effect of person- and study-related factors, and impact on outcomes.
Results: A total of 48 studies, comprising 4446 persons were identified. The estimated enrolment rate was 50.3% (95% confidence interval (CI): 49.6 to 51.1) and the estimated attrition rates in the intervention and control groups were 16.8% (95% CI: 16.2 to 17.3) and 14.4% (95% CI: 13.8 to 14.9), respectively. The main reported reason for refusing to participate was lack of interest (70.6%), while the reported reasons for dropping out were mainly owing to medical issues (26.1%) and disliking the intervention (17.9%). Trial, programme, and patient-related variables were found to influence the enrolment and/or attrition rates. Studies that had a 10% higher attrition rate had an effect size that was larger by 0.19 (95% CI: 0.17 to 0.24).
Conclusion: Greater understanding of the factors associated with enrolment and attrition rates would help in planning and developing a more appealing self-management intervention that patients can easily accept and incorporate into their everyday lives.
Keywords: Self-management; attrition rate; multiple sclerosis; random effect meta-regression.