Exploring long-term follow-up of effective implementation trials in schools: a secondary review

To reduce chronic diseases, evidence-based health promotion interventions (EBIs) must be effectively implemented and sustained in settings such as schools. This review assessed the extent to which EBIs sustained their effects following the completion of an effective implementation trial. It also explored the use of recommended sustainment practices in follow-up studies.

A Cochrane systematic review served as the basis for identifying school health promotion EBIs with demonstrated implementation effectiveness. Eligible studies were controlled trials in elementary or secondary schools that evaluated an implementation intervention and reported a statistically significant implementation effect. Forward citation searches were conducted across three electronic databases and two trial registration databases to identify relevant follow-up studies. To be included, follow-up studies needed to report comparable quantitative data (i.e., similar samples and outcome measures) to the original trial and to have been collected at least 6 months after the intervention ended. Two independent reviewers screened studies and extracted data using a predetermined template, with input from a third reviewer as needed. The included papers were assessed against sustainment-promoting practices, including whether they planned for, defined, or used a sustainment framework. The percentage of the original implementation effect sustained at follow-up was calculated.

Of the 23 EBIs with a significant implementation effect in the original review, 26% (n = 6) were found to have eligible follow-up studies. These targeted physical activity (n = 3), diet (n = 2), and tobacco prevention (n = 1). Four studies reported implementation outcomes, and two reassessed behavioral outcomes. The percentage of the implementation effect sustained ranged from 51 to 122%, with a median of 76% (IQ1 = 56%, IQ3 = 107%).

To the best of our knowledge, this is the first review to quantify the sustainment of EBIs in schools following an effective implementation trial and to assess the extent to which best-practice sustainment principles were applied. Few studies described sustainment planning or used comparable follow-up measures. Improving long-term outcome measurement and integrating sustainment frameworks into planning and implementation could help sustain effective school health promotion EBIs.