A Mobile Health Intervention in Pulmonary Arterial Hypertension

Patients with pulmonary arterial hypertension (PAH) have severely reduced exercise capacity and reduced quality of life. At diagnosis, most PAH patients are New York Heart Association (NYHA) functional class III with symptoms of fatigue and shortness of breath with less than ordinary activity. Physical activity confers multiple benefits relevant to PAH pathophysiology including improvements in endothelial function, energy metabolism, and right ventricular (RV) function. Increasing physical activity is highly efficacious in PAH, resulting in six-minute walk distance (6MWD) improvement that exceeds the effect of medications.

The goal of this proposal is to adapt and test the feasibility of our mHealth intervention to increase physical activity in a geographically diverse PAH population. In secondary aims, we will assess conventional PAH trial outcomes (6MWD, quality of life) and physiologic mechanisms by which increasing activity may improve exercise capacity.

The investigator hypothesizes that an mHealth intervention is feasible and will increase physical activity in subjects with PAH. This study proposes a randomized trial of unblinded step tracking with smart texts tracking for 12 weeks. Participants will wear a display-free triaxial accelerometer, which will continuously transmit data to a compatible smartphone (owned by 75% of our PAH population). Efficacy endpoints have been selected to mirror FDA criteria for drug approval in PAH. The following aims will be tested:

Aim 1: To test the feasibility of an mHealth intervention to increase step counts in patients with PAH. Fifty PAH patients will be randomized to the mHealth intervention or usual activity for 12 weeks. The primary endpoint will be daily step count during Week 12. Secondary endpoints will assess step target achievement, daily activity time, and aerobic time. The fidelity of data collection and text transmission will also be assessed.

Aim 2: To examine the effect of an mHealth intervention on exercise capacity and quality of life. Participants will complete a six minute walk test and the emPHasis-10 questionnaire at baseline and 12 weeks. The primary endpoint will be six minute walk distance. Secondary endpoints will be emPHasis-10 quality of life scale score, Borg dyspnea score, and resting heart rate.

Aim 3: To examine the effect of an mHealth intervention on mechanisms of improved exercise capacity. Subjects will undergo echocardiography, blood draw, and body composition assessment. The primary endpoint will be RV longitudinal strain. Secondary endpoints will be the homeostatic model assessment of insulin resistance, lean muscle and fat mass, and B-type natriuretic peptide.

Inclusion criteria

• Aged 18 or older.
• Diagnosed with idiopathic, heritable, or associated (connective tissue disease, drugs, or toxins) pulmonary arterial hypertension (PAH) according to World Health Organization consensus recommendations.
• Stable PAH-specific medication regimen for three months prior to enrollment. Subjects with only a single diuretic adjustment in the prior three months will be included.
• Subjects must own a Bluetooth capable modern smartphone capable of receiving and sending text messages and an active data plan.

Exclusion criteria

• Prohibited from normal activity due to wheelchair bound status, bed bound status, reliance on a cane/walker, activity-limiting angina, activity-limiting osteoarthritis, or other condition.
• Pregnancy.
• Diagnosis of PAH etiology other than idiopathic, heritable, or associated.
• Forced vital capacity <70% predicted.
• Functional class IV heart failure.
• Requirement of > 1 diuretic adjustment in the prior three months.
• Preferred form of activity is not measured by an activity tracker (swimming, yoga, ice skating, stair master, or activities on wheels such as bicycling or rollerblading).