Table 1.

Primary questions and main findings.

Phase	Primary questions	Main findings
1	Are the previously developed weight loss app features and the connected devices usable by the study sample? Are Fitbit activity tracker and Fitbit Aria scale use helpful for tracking their activity and weight, respectively? What design aspects of the weight loss app need improvement?	Rated easy to use by all participants (rated ≥65 on the System Usability Scale); scores ranged 70 to 92.5 out of a possible 100 Helpful and easy to use devices; no issues noted; positive aspect of devices noted by all participants Difficulty searching for specific foods in the database by 4 participants
2	What CPAPa adherence tracking information is helpful to participants? Which graphical displays about CPAP are easy to interpret? Which CPAP tracking features lead to accurate interpretations by participants?	Less information preferable (eg, AHIb not displayed) Color to indicate mask leak only when there is a problem is preferred Clearly displayed 100% success goal is needed Success depicted as percentage of adherence is easily and accurately interpretable
3	Is the new CPAP module integrated with the weight loss app usable and acceptable to participants?	Found to be not burdensome and has an excellent usability rating; all participants rated >65 on the System Usability Scale with a range of 72.5 to 92.5 Request for reminders at appropriate times of day, that is, reminder 1 hour before bedtime to wear a CPAP device and reminder to synchronize Fitbit in the morning upon waking

^aCPAP: continuous positive airway pressure.

^bAHI: apnea-hypopnea index.