App-Based Versus Standard Six-Minute Walk Test in Pulmonary Hypertension: Mixed Methods Study

Background Pulmonary arterial hypertension (PAH) is a chronic disease of the pulmonary vasculature that can lead to heart failure and premature death. Assessment patients with PAH includes performing 6-minute walk test (6MWT) in clinics. We developed smartphone app compute walked distance (6MWD) indoors, by counting U-turns, outdoors, using satellite positioning. Objective The goal research was assess (1) accuracy indoor 6MWTs clinical settings, (2) validity test-retest reliability outdoor community, (3) compliance, usability, acceptance app, (4) feasibility pulse oximetry during 6MWTs. Methods tested on 30 over 6 months. Patients were asked perform 3 conventional clinic while mode one or more app-based community per month. Results Bland-Altman analysis 70 pairs versus 6MWDs suggests sometimes inaccurate (14.6 m mean difference, lower upper limit agreement: –133.35 162.55 m). comparison 69 community-based within 7 days shows tests are strongly related those performed (correlation 0.89), but interpretation should consider differences above clinically significant threshold not uncommon. Analysis 89 same patient repeatable (intraclass correlation 0.91, standard error measurement 36.97 m, coefficient variation 12.45%). Questionnaires semistructured interviews indicate usable well accepted, motivation use it could be affected if data used for decision, which may explain low compliance 52% our cohort. indicates oximeters unreliable walk. Conclusions App-based settings valid, repeatable, accepted patients. More studies would needed benefits practice. Trial Registration ClinicalTrials.gov NCT04633538; https://clinicaltrials.gov/ct2/show/NCT04633538