Determinants of Exercise Adherence in a Prospective Cohort Study of Patients with Chronic Obstructive Pulmonary Disease: An Application of the Theory of Planned Behavior and the Concept of Alliance

Introduction: Pulmonary rehabilitation is considered an important
method of improving health-related quality of life in patients with
chronic obstructive pulmonary disease. A critical component to the
success of pulmonary rehabilitation is exercise adherence, which is
often lower than 50%. When there is a better understanding on the
psychological determinants of adherence, theory-informed
interventions can be developed to improve adherence. Therefore,
the aim of this study was to examine the utility of the Theory of
Planned Behavior in combination with the therapeutic alliance in
explaining exercise adherence in a prospective cohort study of
pulmonary rehabilitation in patients with chronic obstructive
pulmonary disease to ultimately increase adherence with
psychological interventions. In addition, we examined the influence
of the Theory of Planned Behavior determinants and alliance in
combination with clinical determinants on adherence.
Methods: At baseline, 196 patients from 53 physiotherapy practices
in the Netherlands and Belgium completed measures of the Theory
of Planned Behavior, and disease and demographic characteristics.
After three months they completed measures of alliance. Their
physiotherapist provided exercise adherence measures after 12
months. Data were analyzed using Spearman’s correlations,
hierarchical linear multiple regression analyses and mediation
analysis.
Results: Hierarchical linear multiple regression analyses indicated
that intention ( = 0.72; p < 0.001) and alliance ( = 0.26; p <
0.001) explained 24.8% of the variance in exercise adherence.
After adding Medical Research Council dyspnea score and
depression to the model, 35.6% of the variance could be explained.
Perceived behavioral control, attitude, and alliance, explained
37.9% of variance in exercise intention. The effect of alliance on
adherence was partially mediated by intention.
Conclusion: Extending the Theory of Planned Behavior with the
concept of alliance is a promising innovation to understand exercise
adherence of patients who are coached by a health care
professional. Healthcare providers should obtain information about
their patients’ attitudes, perceived behavioral control, and alliance,
to inform their coaching and further psychosocial interventions.
Concrete recommendations are provided for effectively addressing
these psychosocial determinants of adherence within the patient-coaching relationship.