The impact of motivational interviewing on behavioural change and health outcomes in cancer patients and survivors. A systematic review and meta-analysis.

BACKGROUND: Cancer patients and survivors commonly have poorer health behaviours and subsequent outcomes, often as a result of negative impacts of diagnosis and treatment. Motivational interviewing is reported to be an effective psychological tool to produce a shift in one's behaviour resulting in improved outcomes. However, there is a lack of analyses investigating this tool's impact on healthy behaviours and health outcomes in cancer populations.

OBJECTIVE: To investigate the effect of motivational interviewing on behaviours and health outcomes in cancer populations.

METHODS: The studies were identified from four databases using variations of the terms "cancer" and "motivational interviewing". Randomised trials, non-randomised trials and quasi-experimental studies which contained control (or usual care) comparators were included. Risk of bias was assessed using the Cochrane Risk of Bias Version 5.1.0 and the Risk of Bias In Non-Randomised Studies of Interventions tools. The quality of evidence was assessed using the GRADE framework. Means difference and standardised mean differences and 95 % confidence intervals were used to report the pooled effects using a random effects model.

RESULTS: Twenty-one studies were included in the review and 17 studies were included in the meta-analysis. A total of 1752 cancer patients and survivors received MI as an intervention (or part thereof). Quality of life, anxiety, depression, functional tasks (6-minute walk test), body mass index and body weight (BMI/BW), physical activity (PA), self-efficacy and fatigue were outcomes measured in the selected studies. Effects were seen in functional tasks, physical activity, BMI/BW, depression and self-efficacy. All of these outcomes were from studies that were classed as very low-quality evidence except for BMI/BW and PA, which were from moderate-quality evidence.

CONCLUSION: Motivational interviewing had positive effects on functional tasks, PA, BMI/BW, depression and self-efficacy in people diagnosed with cancer. However, more higher-quality studies need to be conducted to further ascertain the effect of this intervention.