A randomized clinical trial of an activity and exercise adherence intervention in chronic pulmonary disease

Objectives: To evaluate the effectiveness of an exercise adherence intervention to maintain daily activity, adherence to exercise, and exercise capacity over 1 year after completion of an outpatient pulmonary rehabilitation program. Design: A 2-group, experimental design was used with randomization into intervention and usual care groups. Setting: Outpatient pulmonary rehabilitation program in a university-affiliated medical center. Participants: One hundred six subjects (98 men; 98 with chronic obstructive pulmonary disease) with a mean age of 67 years and chronic lung disease. Intervention: Twelve-week adherence intervention (weekly phone calls and home visit) including counseling on establishing, monitoring, and problem-solving in maintaining a home exercise program. Main Outcome Measures: Primary outcomes included daily activity (accelerometer), exercise adherence (exercise diary), and exercise capacity (six-minute walk test). All measures were performed at baseline, after the pulmonary rehabilitation program (8wk), after the adherence intervention (20wk), and at 1 year. Results: A rank-based analysis of covariance showed less decline at 20 weeks in exercise adherence (intervention mean, +3min: control mean, - 13min; P = .015) and exercise capacity (intervention mean. - 10.7m; control mean, -35.4m; P = .023). There were no differences in daily activity at 20 weeks or any differences in any primary variable at 1 year. Conclusions: The intervention enhanced exercise adherence and exercise capacity in the short term but produced no long-term benefit. These bindings are in part attributed to the disappointing measurement characteristics of the accelerometer used to measure daily activity. The intervention was acceptable to participants. Further study is needed to fashion interventions that have more persistent benefit.