Developing NS MedTracker
Introduction to HealthVault
by Burag Cetinkaya
What is HealthVault?
There is a plethora of health applications today. It’s not uncommon for an individual to use three or four applications to manage her weight, prescriptions, doctor visits, etc. Unfortunately each application has its own proprietary way of storing the data. For example, when a user wants to make her weight data available to her doctor, she has to rely on print outs and emails. Microsoft recently announced the HealthVault platform to address this issue by providing an on-line data store, allowing applications to store a user’s health data. It provides a common platform for both devices and applications to manage the health data using a set of web services. These services can be programmed using the HealthVault API.
The user is in the center of this model. It’s up to the user to grant/deny access to applications that integrate with HealthVault. After the user grants access to a requesting application, data can be read/written to the user’s HealthVault account by that particular application. This central model also allows information exchange between applications. For example, if the user has given HealthVault access authorization to both a weight management and patient management system, a doctor using the patient management system can observe the weight fluctuations of a that user as the data becomes available. This enables applications to have access to more data on-demand. One particular area where this can be tremendously useful is decision support systems, wherein more data translates into improved outcome.
Below is a list of some of the major advantages of using HealthVault as a health data exchange platform:
- Storage of data is handled by HealthVault. This means your application will not have to worry about the security, maintenance, backup or regulatory constraints on the data. HealthVault will be in charge of storage and the maintenance of data. With these taken care of, your application can concentrate on providing more functionality and value to users.
- Not having a data migration barrier will make it much easier for users of existing applications to switch over to another application. It will be as easy as signing up for your application, and the user will have all of her health data in the new application within a couple of minutes.
- By integrating with HealthVault your application will have access to device data that previously might not have been available. An accurate and frequent data feed might enable your application to provide functionality that previously hasn’t been possible to deliver.
Who is it for?
There are three consumers of HealthVault services:
- Application developers
- Device manufacturers
- Users
All entities interact with the HealthVault service directly. HealthVault acts like an information exchange hub for all the parties. Below is a diagram illustrating this structure.
Web applications (regardless of their platforms) can use a set of web services to read and write data from HealthVault. There are two ways in which to communicate with the HealthVault:
- Utilizing raw XML requests/responses
- Using the provided HealthVault SDK for .NET
For applications built on the .NET platform, it is appealing to use the set of .NET libraries that are included with the HealthVault SDK. Use of the .NET libraries will significantly reduce the development time since developers will be dealing with .NET classes for all interaction with HealthVault.
For applications that are built on a different platform or that use a non-.NET language, the HealthVault XML API can be utilizied. This API consists of a set of XML web services. Note that doing so will require you to parse the returned XML responses before using the data.
Type of applications and usage scenarios
One thing to keep in mind is that there is no silver bullet when integrating with HealthVault. Depending on the type of the application, integration methods and subsequent design decisions will change. For example, a decision support system will have drastically different data availability requirements than a cycling distance logger application. This, in turn, will affect the architecture of the applications when integrating with HealthVault. Please keep in mind that the sample app that we build will follow only one of the possible integration approaches with HealthVault.
Devices also will be able to send data directly to the HealthVault. HealthVault provides a desktop client that is able to recognize the connected devices and upload the data to the cloud. Device manufacturers will have to utilize the HealthVault DDK to benefit from this service.
Anyone with a Live ID account can sign up for a free HealthVault account. Once an account has been created, the user will have access to a list of applications that integrate with the HealthVault. Some of these applications are free while others require a fee for use. After signing up for a service, a user can return to the HealthVault web site to manage the applications’ access, and can also see the data available in the HealthVault.
How are all consumers of the HealthVault platform connected?
Let’s take a look at a scenario to explain the interaction between all consumers of the HealthVault platform. Jay is a 50-year-old diabetic patient. He routinely takes blood glucose measurements at home using a device and records the values by hand. His doctor, Mary, gets a copy of these measurements to monitor the changes in his blood glucose in order to regulate the dosage of the insulin shots he receives. Jay, then takes the prescription and gets the new dosage from his pharmacy. Due to the manual nature of this process, Mary can only see the fluctuations every two weeks, she has to keep a separate record of this data for internal tracking purposes. Jay is recording the values by hand each day.
In a HealthVault-powered ecosystem, Jay uses his blood glucose measurement device to take the measurements. After taking the measurement, he connects the device to his laptop. New data results are automatically synchronized with Jay’s HealthVault account.
Jay then authorizes Mary to retrieve his health information in HealthVault using the HealthVault web site. This enables Mary to regularly monitor Jay’s blood glucose measurement fluctuations every day as more data becomes available.
Mary then uses a web application that integrates with HealthVault and retrieves new information about all her patients every night. The application also helps her chart the measurements over a period of time and correlate this information with the prescribed dosages of insulin. She also has the ability to track the fluctuations in values and overlay information about different medications that Jay was receiving. Consequently, she has access to more information about Jay’s reactions to different medications.
Alternatively, this application can send a reminder to Jay for an earlier foot/eye examination (a common exam for diabetic patients) if Mary notices an abnormal change in the measurements. In this ecosystem, there is no delay in the delivery of information. The patient and the primary care physician (PCP) can share medical records much more efficiently and be proactive about possible changes in patient conditions.
Here is a screenshot from the HealthVault illustration prepared by XPLANE that shows the envisioned future of a HealthVault ecosystem.
What will we do in this series?
We will create a web application using ASP.NET and HealthVault SDK that tracks a user’s medications. This application will enable the user to track the medications she is taking over time. We will add more functionality as we go along.
We will be using the following technologies:
- ASP.NET 3.5
- Microsoft Health Vault SDK
Continue on to part 1 of this series.