Currently, only three of 22 apps on the list feature Apple Watch support, including Hospital RN, Field Connect and Incident Aware.
With the upcoming iOS 9 update, the iPhone's Health app will finally be able to track a woman's period; Siri will get the ability to start/stop a workout.
The health system will release several Apple Watch and iOS apps for patients, as well as an iOS application targeted at physicians.
Although the company's CEO Tim Cook hasn't shared any figures, the research firm looked at the iPhone maker's earnings to get to the estimate.
In the period between April and June, the iPhone maker has sold 3.6 million units of the Apple Watch, representing 20 percent of all wearables shipped.
The research is looking to develop an effective method for predicting seizures; the apps for the study are now in beta testing, and should be out on Sept. 18.
WatchOS 2.0 will bring a number of new features, including timelapse backgrounds, third party complications, time travel, transit info and GoPro integration.
The application enables seniors in distress to alert and contact their caregivers with a simple tap on the wrist, wherever they are.
The new offering uses the same technology as smartphone-based AliveECG, relying on a single-lead sensor built into a replacement watchband.
Nearly two-thirds of Apple's wearable users are exercising more often and for longer periods of time, according to a survey involving 1,500 users.