After an in-depth review of Medicare Advantage provider directories revealed systemic inaccuracies, the federal government is warning insurers that they must clean up their act.

The Centers for Medicare & Medicaid Services previously revealed some results of the review, which focused on primary care physicians, cardiologists, ophthalmologists and oncologists.

In its final report (PDF) released last week, CMS says that of the 5,832 providers in the review, 46.9% had at least one deficiency. The agency also listed the names and results of the 54 health plans involved in the audit, plus the compliance actions taken against them.

Here’s a look at the results:

  • Two insurers—the Kaiser Foundation Health Plan and CommunityCare Managed Healthcare Plans of OK—had considerably lower rates of inaccuracies than the rest, and were the only two against which CMS took no compliance action.
  • WellCare Health Plans, EmblemHealth and Piedmont Community Health Plan, all of which had the highest error rates, all received a “warning letter with request for a business plan” that describes how they plan to address the problems identified.
  • In addition to those three warning letters, CMS issued 31 notices of non-compliance and 18 warning letters to plans involved in the review.
  • The average error rate among the 54 plans reviewed was 38%.
Source: Centers for Medicare & Medicaid Services

One common reason for directory inaccuracies, CMS says, is that a group practice will often list a provider at a location because the group has an office there, “even if that specific provider rarely or never sees patients at that location,” the report says. In addition, MA plans seem to rely on credentialing services, vendor support and provider responses to ensure directory accuracy, rather than implementing their own internal oversight.

Lastly, the agency notes that “we encountered several instances where a call to a provider’s office resulted in determining that the provider had been retired or deceased for a long period of time, sometimes years.” And in some instances, when CMS called a provider’s office directly, the agency discovered incorrect information that providers themselves had verified when the MA plans called them.

CMS says it is giving MA plans that were notified of deficiencies 30 days to make the necessary corrections to achieve compliance. The agency suggests MA plans look into “near-term solutions” such as: performing self-audits of directory data, working with group practices to ensure that providers are only listed at locations where they accept appointments, and developing better internal processes for members to report directory errors.

If insurers don’t correct the errors, they could face sanctions including a suspension of MA plan marketing and enrollment, according to Kaiser Health News. Cigna recently faced similar penalties for what CMS said was “substantial failures” in its MA and Part D plan compliance.