The Effectiveness of Randomized Controlled Trials to Improve Dietary Intake in the Context of Cardiovascular Disease Prevention and Management in Rural Communities: A Systematic Review.

BACKGROUND:Dietary intake is an important modifiable risk factor for cardiovascular disease. However, to our knowledge, there are no systematic reviews of nutrition interventions in the context of cardiovascular disease prevention and management within rural communities. This is important to investigate, given the unique geographic, social, and contextual factors associated with rurality. OBJECTIVE:Our primary objective was to systematically assess evidence on the effectiveness of randomized controlled trials to improve dietary intake in the context of cardiovascular disease prevention and management in rural communities. METHODS:Nine electronic databases were searched from inception to June 2020, including MEDLINE, The Cochrane Library, Embase, Emcare, PsycINFO, Scopus, Rural and Remote Health, CINAHL, and AMED. Randomized controlled trials that reported results of interventions with adult, rural populations and measured change in dietary intake compared to usual care, alternative intervention, or no intervention controls were included. Included randomized controlled trials were also assessed according to the TIDieR (Template for Intervention Description and Reporting) checklist and RE-AIM (reach, effectiveness, adoption, implementation, maintenance) framework. RESULTS:Thirteen articles reporting results of randomized controlled trials were identified. Included articles reported a range of nutrition interventions and measured 18 dietary intake outcomes. Most studies (n = 10) demonstrated effectiveness in altering at least 1 dietary intake outcome, including fruit and/or vegetable (n = 9), fiber (n = 2), Dietary Risk Assessment score (n = 2), energy, dairy, carotene, vitamin C and sodium (all n = 1). However, there was wide variation in the reporting of intervention components (according to the TIDieR checklist) and impact (according to RE-AIM framework), resulting in difficulty interpreting the "real-world" implications of these results. CONCLUSIONS:Through this systematic review, we found limited evidence of improvement in dietary intakes due to nutrition interventions in the context of cardiovascular disease prevention and management in rural communities. Fruit and/or vegetable intakes were the most frequently reported dietary intake outcomes, and most likely to be improved across the included studies. Included studies were generally not well reported, which may hinder replication by clinicians and consolidation of the evidence base by other researchers. Given the substantial burden of cardiovascular disease experienced by those living in rural areas of developed countries, additional high-quality nutrition research that acknowledges the complexities of rural health is required.