Effectiveness of primary preventive programmes using motivational interviewing to support cardiovascular risk factor modification in individuals at increased risk; a systematic review and meta-analysis of randomised controlled trials

Background: Programmes using motivational interviewing, are promising in encouraging lifestyle change, but have not been well established and explored. The objectives of this systematic review and meta-analysis was to determine the effectiveness of motivational interviewing in supporting modifiable risk factor change, in individuals at increased cardiovascular risk.

Methods: Systematic review and meta-analysis with results reported using Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Health related data bases were searched for randomised controlled trials, from February 2013 to August 2018. Criteria for inclusion included; preventive programmes, using motivational interviewing principles, aiming to modify cardiovascular risk factors in adults of both genders, representing all ethnicities and employment status, and having at least one or more modifiable cardiovascular risk factor/s. Two reviewers independently conducted a quality appraisal of included studies using an adapted Cochrane framework.

Results: Seven studies met inclusion criteria. No statistical difference between groups for smoking status and physical activity were reported. A random effects analysis from 3 studies, determined a synthesized estimate for standardised mean difference in weight of -2.60kg (95% CI –4.793 to -0.404 kg; p=0.005), with high statistical heterogeneity. Pooled results from 2 studies, determined a mean difference in LDL-c of 0.43mg/dl, but was insignificant. A range of possible effective intervention characteristics were identified: application of affirmation, compassion and evocation, combined with education, consisting of 1 in person and 12 telephone-based sessions of 15 to 30 minutes each for 12 consecutive weeks, delivered by a nurse expert in MI through an outpatient-clinic.

Discussion: While motivational interviewing may support individuals to modify risk, its effectiveness remains uncertain. Methodological quality to date is limited, having studies contaminated with performance, detection and reporting bias. Application of motivational interviewing was found to be insufficiently reported across all studies. Its strengths and limitations need to be explored further, through robust studies.