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Federal Audit Found Every Sampled Medicare Advantage Stroke Code Lacked Medical Record Support
An HHS Office of Inspector General audit published in May 2026 found that acute stroke diagnosis codes submitted by Medicare Advantage plans were entirely unsupported by patient records, tied to potential overpayments of 462 million dollars for payment year 2021.
By the Goodsurance editorial teamJuly 8, 2026
A May 2026 audit by the HHS Office of Inspector General examined whether Medicare Advantage organizations properly supported acute stroke diagnosis codes submitted to CMS for risk adjustment purposes.
Of 97 enrollees reviewed across multiple Medicare Advantage organizations, every single submitted acute stroke diagnosis code, 100 percent of the sample, was not supported by the patient's medical records.
Medicare Advantage plans are paid partly based on documented enrollee health status. Plans submit diagnosis codes to CMS, and codes indicating more serious conditions result in higher per-enrollee payments. The OIG found that the unsupported acute stroke codes correspond to potential overpayments of 462 million dollars to Medicare Advantage organizations for payment year 2021.
The OIG recommended CMS establish processes to better detect problematic submissions before payments are made.
Risk adjustment auditing has been a persistent point of dispute between federal regulators and the insurance industry. Medicare Advantage plans have challenged government audit methodologies in prior cases. The acute stroke finding adds to a body of OIG work questioning whether risk-adjustment payments consistently align with diagnoses that medical records support. CMS has authority to recoup overpayments, though the process can be lengthy.
In plain words
Medicare Advantage plans tell the government how sick their patients are. Sicker patients mean higher payments to the plan. The government uses diagnosis codes to decide how much to pay. A federal watchdog called the OIG checked Medicare Advantage plans that sent in codes saying patients had severe strokes. They looked at 97 patients' records. Not one record backed up the stroke diagnosis reported. The OIG said those unsupported codes could have led to overpayments of 462 million dollars for the year 2021. The OIG told CMS to create better ways to catch these problems before paying out. Plans can dispute the findings and recovering overpayments can take a long time.
Understand the basics first
Source: Medicare Rights Center
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