RESUMO
BACKGROUND: The current approach to the outpatient management of heart failure involves patients recollecting what has happened to them since their last clinic visit. But patients' recollection of their symptoms may not be sufficiently accurate to optimally manage their disease. Most of what is known about heart failure is related to patients' diurnal symptoms and activities. Some mobile electronic technologies can operate continuously to collect data from the time patients go to bed until they get up in the morning. We were therefore interested to evaluate if patients would use a system of selected patient-facing devices to collect physiologic and subjective state data in and around the patients' period of sleep, and if there were differences in device use and perceptions of usability at the device level METHODS: This descriptive observational study of home-dwelling patients with heart failure, between 21 and 90 years of age, enrolled in an outpatient heart failure clinic was conducted between December 2014 and June 2015. Patients received five devices, namely, body weight scale, blood pressure device, an iPad-based subjective states assessment, pulse oximeter, and actigraph, to collect their physiologic (body weight, blood pressure, heart rate, blood oxygen saturation, and physical activity) and subjective state data (symptoms and subjective states) at home for the next six consecutive nights. Use was defined as the ratio of observed use over expected use, where 1.0 is observed equals expected. Usability was determined by the overall System Usability Scale score. RESULTS: Participants were 39 clinical heart failure patients, mean age 68.1 (SD, 12.3), 72% male, 62% African American. The ratio of observed over expected use for the body weight scale, blood pressure device, iPad application, pulse oximeter and actigraph was 0.8, 1.0, 1.1, 0.9, and 1.9, respectively. The mean overall System Usability Scale score for each device were 84.5, 89.7, 85.7, 87.6, and 85.2, respectively. CONCLUSIONS: Patients were able to use all of the devices and they rated the usability of all the devices higher than expected. Our study provides support for at-home patient-collected physiologic and subjective state data. To our knowledge, this is the first study to assess the use and usability of electronic objective and subjective data collection devices in heart failure patients' homes overnight.