Effectiveness of a motivational interviewing intervention on weight loss, physical activity and cardiovascular disease risk factors: a randomized controlled trial with a 12- month post- intervention follow-up Gabrielle Sherer Rotation: WPNC Preceptor: Elizabeth Koustis MS RD LD

Citation Hardcastle SJ, Taylor AH, Bailey MP, Harley RA, Hagger MS. Effectiveness of a motivational interviewing intervention on weight loss, physical activity and cardiovascular disease risk factors: a randomized controlled trial with a 12- month post-intervention follow-up. Int J Behav Nutr Phys Act. 2013; 10:

Background Traditional obesity interventions in the primary care setting focused on changes in diet and physical activity behaviors shown to result in clinically significant wt reduction – Drawbacks: intensive, require considerable financial and human resources, often not translated to long term results MI intervention in studies lasting 6 mo or less shown to result in – Increased physical activity – Reduced caloric intake – Decreased BMI

Spirit of Motivational Interviewing Collaboration – Practitioner is a supportive partner, not a persuasive expert Evocation – Draw out pt’s personal motives for behavior change using their perceptions and values – Elicit rather than impart wisdom and knowledge Autonomy – Responsibility, ability, and decision to make behavioral changes are in pt’s control

Motivational Interviewing Provides components that support psychological needs – Self-determination theory Linked with the enhancement of self-efficacy – Social cognitive theory Linked to increasing motivational readiness to change – Transtheoretical model

Objective Assess whether changes in weight, BMI, physical activity, and CVD risk factors within the intervention group were maintained one-year later. Explore the effect of counseling session attendance (dose) on maintenance outcomes. Examine the effects of motivational interviewing on outcomes for sub-groups presenting with specific CVD risk factors at baseline.

Participants and Setting Inclusion – yo – At least one CVD risk factor Excess weight BMI >/=28 HTN 150/90 mmHg Hypercholersterolemia >/= 5.2 mmol.l -1 Primary care health centers- UK

Design Baseline biochemical/anthropometric assessment conducted by trained nurses All participants received a standard information leaflet on exercise and nutrition – Consume five portions of fruit and vegetables per day – Recommended fat intake – Recommendation to be physically active for 30 min, five times a week – physiological and psychological benefits of increased physical activity – food and physical activity quiz with advice depending upon scores Intervention group: face-to-face consultation with a physical activity specialist or registered dietician – Opportunity to meet on up to four further occasions, for 20 to 30 mins, within the following 6 mo – Not encouraged to attend a certain number of sessions 18 months post-baseline: all participants invited to a final assessment

Intervention Stage Matched Approach – Precontemplative, contemplative, preparation, action, maitnance Typical strategies – Ambivalent pts: agenda setting exploration of the pros and cons importance and confidence rulers – Sufficiently motivated: strengthening commitment negotiating a change plan

Outcome Measures Weight, height, systolic, and diastolic blood pressure (SBP/DBP), and fasting cholesterol Physical activity – short interview version of the International Physical Activity Questionnaire- intensity, frequency, and duration of activity in the previous 7 days Physical activity stage of change – ‘yes’ or ‘no’ answer to five questions in a flowchart format Fat intake – DINE food frequency questionnaire Fruit and vegetable consumption – five-a-day Community Evaluation Tool questionnaire (FACET)

Statistical Analysis Satisfactory randomization – 2 MANOVAs with behavioral and biomedical outcome variables as dependent variables and intervention group as an independent variables Effects of the MI intervention on each behavioral and biomedical outcome variable – 3 (time: baseline vs. 6-month follow-up vs. 18-month follow up) × 2 (group: MI intervention vs. minimal intervention) mixed-model ANCOVAs – Bonferroni correction for multiple comparisons – Age, gender, and smoking status entered as covariates in each model Effect of number of sessions attended on change in behavioral and outcome measures – Hierarchical linear multiple regression analyses with number of sessions, as a continuous independent variable Effects of intervention on relevant biomedical outcome variables in groups of participants that exhibited corresponding specific risk factors at baseline – 3 (time: baseline vs. 6-month follow-up vs. 18-month follow up) × 2 (group: MI intervention vs. minimal intervention) mixed-model ANCOVA – Bonferroni correction for multiple comparisons

Results- Intervention effects MI intervention group Walking- increase between baseline and 6-months (p =.006, d = 0.24) and between baseline and 18-months (p =.032, d = 0.20) -sustained change over the follow- up period Stage of change- increase between baseline and 6-months (p<. 001, d = 0.33), returned to near baseline levels at 18 months (p <. 001, d = 0.29) Dietary fat intake-no difference in the MI intervention group BMI- no significant changes DBP- drop from baseline to 6-months (p<. 001, d = 0.29) Cholesterol- reduced between baseline and 6-months (p =.008, d = 0.23) - maintained at 18-months (p =. 015, d = 0.22) Control group No effect on walking scores over time No changes between baseline and 6- months and a significant decrease between baseline and 18-month (p<.001, d = 0.27) Decrease in dietary fat intake between baseline and 6-month (p<.001, d = 0.43), maintained at 18 months (p<.001, d = 0.38) Increase in BMI between 6- and 18-month (p=.007, d = 0.21) No change in DBP increase in cholesterol between 6 and 18 months (p =.007, d = 0.30).

Results- Dose More sessions attended = greater reduction in triglycerides (β = −0.20, t= −2.54, p=.012, d = 0.28)

Results- Subgroups MI Intervention Group BMI in obese patients - decrease in BMI between baseline and 6-months (p =.010, d = 0.26) /no differences between baseline and 18- months Cholesterol in hypercholesterolemic patients- decrease in cholesterol levels between baseline and 6-months (p =.005, d = 0.31) and between baseline and 18-months (p =.003, d = 0.33) Control Group Increase in BMI at 18- months compared to both baseline (p =.015, d = 0.30) and 6-months (p =.037, d = 0.26) no significant changes in cholesterol levels

Conclusions It is possible for a MI intervention to lead to significant behavior changes and biomedical outcomes (inc walking and dec cholesterol) that can be maintained for 12 months after intervention Changes in the outcome variables were not associated with the number of sessions attended-effects appear to be in response to a relatively low dose of MI (average attendance 2 sessions) MI intervention can lead to a sustained decrease in BMI for patients who were obese at baseline. Future research should seek to further examine the dose effects of number of MI sessions and also elucidate the mechanisms behind these changes

Limitations Low participation rate (28%) Important biomedical markers (insulin and HbA1C) not measured Minimal practitioner training (2 four hour training, 3 videotaped sessions) Self-reported measures of physical activity and dietary intake

Clinical Implications Even low doses of MI can lead to some, sustained behavioral and biochemical improvements and can be a good alternative to traditional prescriptive interventions. MI in group settings like Move?