Systematic Review of the Effectiveness of health behavior interventions based on TTM

Introduction Individuals contribute to their own health. Focus should be on individual based interventions. Reducing early mortality and morbidity through interventions focused on lifestyle changes. Interventions for modifying risk behaviors have been based on stage theories, such as TTM. MIYUKI

Stage-based models of behavior change Propose that behavior change is not a continuous process, but a series of qualitatively different stages. The barriers people face in trying to change their behavior differ at different stages in the change process. Thus interventions will be most effective when they are tailored to an individual’s current stage of change. Stage based models are distinguished into three broad categories of individuals 1)Individuals who have not decided to change behavior 2)Decided to change 3)Already engaged in the change process 4)MIYUKI

Usefulness of Stage Models Intuitive and theoretical plausibility. Ability to explain the effectiveness of individual based interventions. Ability to explain the ineffectiveness of ‘one size fits all’ interventions. BHAKTI

Stages of TTM 1)Precontemplation (PC): No intention to change within the next 6 months. 2)Contemplation (C): Intention to change within next 1-6 months. 3)Preparation (PR): Intention to change within the next month or so. 4)Action (A): Implemented the change behavior for less than 6 months. 5)Maintenance (M): Behavior change extending beyond 6 months 6)BHAKTI Motivational Action

Processes and measures of change Proposes ten processes of change These processes are independent variables. These are the activities individuals involve in to overcome stage specific barriers. Measures of change Decisional Balance Scale: Pros and cons of behavior change. Self-efficacy/Temptation: Confidence in their ability to change. These are dependent variables that are sensitive to progress through all stages. BHAKTI

Literature reviews: Predominant explanations 1)Arguments concerning effectiveness of interventions should be based on best available evidence,i.e., Randomized Controlled Trials (RCT). Spencer and Riemsma study 2)Stage based interventions are more effective in modifying certain behaviors over others 3)Proxy measures such as increase in knowledge and stage progression are valid and accurate indicators of the models effectiveness as the basis for intervention. 4)BHAKTI

Study Aims 1)To assess methodological quality of interventions based on the TTM. 2)To determine whether TTM interventions are effective in promoting behavioral change. 3)To examine whether some behaviors are more amenable to TTM interventions, if necessary, to explore other potential sources of heterogeneity. 4)To investigate whether TTM interventions are effective in facilitating stage progression. 5)BHAKTI

Measurements used in the study Trials focused on seven target behaviors, namely, smoking cessation, physical activity, dietary change, multiple lifestyle changes, screening mammography, treatment adherence and the context of mental illness and preventing the uptake of unhealthy behaviors. Interventions were classified based on effectiveness into Positive (Significant outcome in favor of the stage based intervention) No significant differences between groups Negative (Intervention performed was worse than the control) Inconclusive (e.g. losses to follow up) BHAKTI

Results of the study The study showed that there is limited evidence that interventions based on the TTM are more effective in changing behavior when compared with either non-stage-based interventions or when compared to no interventions or usual care. miyuki

PositiveNo significant difference NegativeInconclusive Smoking Cessation4802 Physical Activity1403 Dietary Change2202 Multiple Lifestyle Changes 1303 Screening Mammography 2100 Treatment Adherence 1000 Prevention0201 Total

Discussion First Aim Mixed methodological studies Variable- RCT, cross sectional, etc Poor Second Aim Limited evidence for effectiveness of intervention based on TTM In favor -11 comparison No difference between groups - 20 comparison Inconclusive - 11 comparison CHIDI

Discussion Contd. Third Aim No evidence supporting TTM intervention effectiveness is influence by behavior being targeted No positive evidence between specific behavior and intervention effectiveness Fourth Aim No evidence to support promoting stage progression using TTM intervention would be more effective 18 comparison In favor of TTM- 6 reported significant forward stage movement No difference - 7 Inconclusive or either not reported- 5 CHIDI

Discussion Contd. Reason for favorable Effect of TTM?? Authors suggested TTM lacked effectiveness yet. Many studies favored Intensive intervention More personalized than control participants Intervention contact- Reporting, Comparable control condition Lack of clear source of heterogeneity CHIDI

Reasons for Lack of Evidence - Authors suggestion Poor Application More general heuristic in terms of experiential and behavioral No precise prediction about process to overcoming barrier to stage progression Lack of Model Specification Failed to examine effect of other component like Process of change Decisional balance Self efficacy and Temptation BHAKTI

Reasons for Lack of Evidence - Authors suggestion Variable not Theory Stage of change construct is variable not theory Conceptually flawed studies Inappropriate intervention delivery Static and incomplete interventions tailored to only one point in time Limited level of validation Concern about reliability and validity of stage change based on TTM? MIYUKI

Future Research Establishment of evidence base not in terms of effectiveness but central TTM propositions Greater model specification that reflect methodologically rigorous evidence More thorough descriptions and reporting of intervention contents CHIDI

Conclusion Limited methodological quality and effectiveness of TTM intervention to either facilitate health behavior change or promote stage progression. CHIDI