"GCP’s security practices allow us to have a HIPAA BAA covering GCP’s entire infrastructure, not a set aside portion of our cloud. As a result, you are not restricted to a specific region which has scalability, operational and architectural benefits. You can also benefit from multi-regional service redundancy as well as the ability to use Preemptible VMs to reduce costs.
The security and compliance measures that allow us to support HIPAA compliance are deeply ingrained in our infrastructure, security design, and products. As such, we can offer HIPAA regulated customers the same products at the same pricing that is available to all customers, including sustained use discounts. Other public clouds charge more money for their HIPAA cloud, we do not."
https://cloud.google.com/security/compliance/hipaa/#covered-...
Its been about a year since I last checked out everything you need to be HIPAA compliant to run AWS services, but IIRC it required running dedicated instances for nearly everything. That can make running on AWS way more expensive.
EDIT: Apparently the limitation of dedicated instances was removed in May 2017. https://aws.amazon.com/compliance/hipaa-compliance/