There are federal mandatory reporting laws (see below) in the USA, but some states have them as well. As of April 2007, more than half of states (27) had passed legislation or created regulations related to hospital reporting of adverse events (according to AHRQ at this link)
States that by law require
Mandatory Notification of Adverse Events to Patients
Nevada NRS §439.855 (2004)
Florida Stat. §395.1051 (2004)
New Jersey Stat. §26:2H-12.25 (2005)
Pennsylvania 40 P.S. §1303.308(b) (2004)
Vermont § 310 (2006)
The above are states with laws specifically addressing mandatory reporting. There also are states like Ohio that simply require physicians to obey the AMA's code of ethics, and that code requires that they report. So in a roundabout way they require notification of adverse events. But that is almost never done and no one is in charge of enforcing it.
Federal Regulation Mandates
Reporting in Hospitals
with virtually no compliance
In order to participate in Medicare and Medicaid programs, federal regulations require hospitals to develop and maintain quality assessment and performance improvement programs (QAPI). To comply with that hospitals must measure, analyze, and track quality indicators (in other words "outcomes"), including adverse patient events. State agencies perform survey and review functions for Medicare to certify that hospitals comply with these Federal requirements.
Here is how well that works. A 2010 review conducted by Health and Human Services found that hospitals accurately report adverse events only about 2% of the time (see reporting never events), close enough to zero to regard it as that. And that is fine according to the health care professionals to whom we talk. They say that things that go right are reported and that is what is important. They do not get it.
There even is a regulation specific to medical devices
The reporting of adverse outcomes associated with the use of medical devices is a requirement set forth in the Code of Federal Regulation, Title 21, Section 803. Unfortunately, just as with other such regulations requiring reporting, neither manufacturers nor practitioners nor hospitals nor specialty organizations obey it. If you want a specific instance of how this results in patients dying while all of the above treat the deaths as business as usual and disregard the regulation, do a search on morcellation.
As of April 2007, more than half of states (27) had passed legislation or created regulations related to hospital reporting of adverse events. (From AHRQ at:https://psnet.ahrq.gov/perspectives/perspective/43/advancing-patient-safety-through-state-reporting-systems#ref2). It has been a while since I researched it.