SAS 70 (or SSAE 16) alone does not make you 'compliant'. Technically you can't sell a ""HIPAA Compliant"" anything. You can say your system has the features that can assist with your compliancy, but only a compliance officer or HIPAA auditor can determine if a specific installation is compliant.
We've sold ERP systems for drug manufacturers and compliancy is big, but in the end you can follow the rules but somebody else has to 'officially bless it'.
SSAE 16 (or SAS 70) tells you the data center is physically and electronically secure, but that doesn't mean the clients data is or isn't encrypted (per HIPAA rules). That's up to the vendor or end user who using the data center.
For example, dropbox is very much not secure because although they encrypt data, all customers data is encrypted with a common key. If that key gets out (which it did a while back requiring a massive rekeying), then all customers data is now as good as unencrypted. This is how Bluray was cracked. Plus my guess is the NSA can still crack it because they paid big encryption vendors (like RSA) big bucks to install back doors.
Alot of clients who think they are complying with HIPAA often have huge exposure because of their backup systems. IE some IT guy takes all the data home for the offsite rotation, or puts it in a directory for transmission to some cheapo cloud backup service like Carbonite (not so secure LOL). In many cases, the transmission (in flight as its called) isn't even encrypted. Of course....shameless plug...
www.eversafe-backup.com fully complies with HIPAA requirements because the data is stored on the local appliance encrypted (256bit), is transmitted to the data center encrypted, and stored (""at rest"") in the SSAE 16 data centers encrypted. More importantly, each customer get their own encryption key and you can even have each individual server backed up have an independent key. If the customer loses their half of the key, however, they ain't ever getting their data back (similar to the joys of Cryptolocker)
I'd bet 50% of the companies who have to comply with HIPAA or even PCI-DSS (credit card) have a failpoint weak link. It usually doesn't matter until they have a breach and then get creamed by government and civil lawsuits....Target...cough cough...