A Mobile Health Intervention to Increase Physical Activity in Pulmonary Arterial Hypertension

Abstract

Background: Supervised exercise training improves outcomes in patients with pulmonary arterial hypertension (PAH). The effect of an unsupervised activity intervention has not been tested.

Research question: Can a text-based mobile health intervention increase step counts in patients with PAH?

Study design and methods: We performed a randomized, parallel arm, single-blind clinical trial. We randomized patients to usual care or a text message-based intervention for 12 weeks. The intervention arm received three automated text messages per day with real-time step count updates and encouraging messages rooted in behavioral change theory. Individual step targets increased by 20% every 4 weeks. The primary end point was mean week 12 step counts. Secondary end points included the 6-min walk test, quality of life, right ventricular function, and body composition.

Results: Among 42 randomized participants, the change in raw steps between baseline and week 12 was higher in the intervention group (1,409 steps [interquartile range, -32 to 2,220] vs -149 steps [interquartile range, -1,010 to 735]; P = .02), which persisted after adjustment for age, sex, baseline step counts, and functional class (model estimated difference, 1,250 steps; P = .03). The intervention arm took a higher average number of steps on all days between days 9 and 84 (P < .05, all days). There was no difference in week 12 six-minute walk distance. Analysis of secondary end points suggested improvements in the emPHasis-10 score (adjusted change, -4.2; P = .046), a reduction in visceral fat volume (adjusted change, -170 mL; P = .023), and nearly significant improvement in tricuspid annular plane systolic excursion (model estimated difference, 1.2 mm; P = .051).

Interpretation: This study demonstrated the feasibility of an automated text message-based intervention to increase physical activity in patients with PAH. Additional studies are warranted to examine the effect of the intervention on clinical outcomes.

Clinical trial registration: ClinicalTrials.gov; No. NCT03069716; URL: www.clinicaltrials.gov.

Keywords: clinical trial; exercise; mobile health technology; pulmonary arterial hypertension.

Copyright © 2021 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Figures

Graphical abstract

Figure 1

Flow diagram of participant enrollment. Only a minority of excluded but eligible individuals (n = 10 of 89) declined to participate due to lack of interest. Most of the patients who dropped out (six of eight) during the run-in period and after randomization did so because of personal reasons rather than dissatisfaction with the study protocol. #No week 12 in-person visit was performed for the last subject because research protocols were placed on hold, due to the SARS-CoV-2 pandemic. Patient-reported outcomes and activity monitoring data were captured for this subject. PAH = pulmonary arterial hypertension; SAE = severe adverse event.

Figure 2

Effect of the mobile health intervention on daily step counts over 12 weeks. We conducted generalized least-squares analysis adjusting for intervention group, days, intervention group × day interaction, baseline steps, age, sex, and World Health Organization functional class. A, Model-based daily steps for each treatment group. B, The model-based difference in daily steps between groups. At the end of the study, those in the intervention group averaged a significantly greater number of daily steps (+1,019; 95% CI, 420-1,619; P < .001) compared with the control group. The intervention group × day interaction was significant (P < .05) on all days between day 9 and day 84, meaning that average step counts in the intervention group were significantly higher than in the control group on each of those days. Tx = treatment.