Background: Patients with asthma engage in less physical activity than peers without asthma. Protocols are needed to prudently increase physical activity in asthma patients. We evaluated whether an educational intervention enhanced with positive-affect induction and self-affirmation was more effective than the educational protocol alone in increasing physical activity in asthma patients.
Methods: We conducted a randomized trial in New York City from September 28, 2004, through July 5, 2007; of 258 asthma patients, 252 completed the trial. At enrollment, control subjects completed a survey measuring energy expenditure, made a contract to increase physical activity, received a pedometer and an asthma workbook, and then underwent bimonthly follow-up telephone calls. Intervention patients received this protocol plus small gifts and instructions in fostering positive affect and self-affirmation. The main outcome was the within-patient change in energy expenditure in kilocalories per week from enrollment to 12 months with an intent-to-treat analysis.
Results: Mean (SD) energy expenditure at enrollment was 1767 (1686) kcal/wk among controls and 1860 (1633) kcal/wk among intervention patients (P = .65) and increased by 415 (95% CI, 76-754; P = .02) and 398 (95% CI, 145-652; P = .002) kcal/wk, respectively, with no difference between groups (P = .94). For both groups, energy expenditure was sustained through 12 months. No adverse events were attributed to the trial. In multivariate analysis, increased energy expenditure was associated with less social support, decreased depressive symptoms, more follow-up calls, use of the pedometer, fulfillment of the contract, and the intervention among patients who required urgent asthma care (all P < .10, 2-sided test).
Conclusions: A multiple-component protocol was effective in increasing physical activity in asthma patients, but an intervention to increase positive affect and self-affirmation was not effective within this protocol. The intervention may have had some benefit, however, in the subgroup of patients who required urgent asthma care during the trial. Trial Registration clinicaltrials.gov Identifier: NCT00195117.