OIG audits Humana, Aetna for Medicare Advantage overpayments: 10 things to know

Subsidiaries of Aetna and Humana received millions in Medicare Advantage overpayments in 2017 and 2018, the HHS Office of Inspector General alleged in audits published Sept. 25. 

The OIG estimated that Humana received $13.1 million in overpayments for one MA contract in 2017 and 2018. The audited contract served around 250,000 enrollees in 2018. 

In a separate audit, the OIG estimated that HealthAssurance Pennsylvania, an Aetna subsidiary, received $4.2 million in overpayments between 2017 and 2018. 

Here are 10 things to know: 

1. The OIG audits Medicare Advantage plans to determine if diagnosis codes submitted to CMS are in line with federal requirements. 
   
   
2. Diagnosis codes determine how much MA plans are reimbursed by CMS. Nearly every major Medicare Advantage plan has faced or settled allegations of upcoding, the practice of making patients appear sicker than they are on paper to receive higher reimbursements from CMS. 
   
   
3. The OIG frequently audits plans for overpayments. The agency published at least 10 audits of Medicare Advantage plans in 2023. 
   
   
4. The OIG recommended Aetna repay $4.2 million it received in overpayments. 
   
   
5. The watchdog recommended Humana repay $6.8 million. The agency did not request the full amount of estimated overpayments because the agency cannot request estimated overpayments from contract years prior to 2018. 
   
   
6. In 2023, CMS finalized tougher audit standards that apply to contract years 2018 and beyond. The move could leave payers on the hook for billions in repayment to the federal government. 
   
   
7. In 2023, Humana challenged the new audit rules in court. The challenge is ongoing. 
   
   
8. A Humana spokesperson told Becker's the company has "consistently called for CMS to audit every plan, every year using the right methodology that is consistent with the underlying principles of the Medicare Advantage model." In its response published in the OIG's report, Humana disputed the agency's audit methodology and disagreed with its recommendation to refund overpayments. 
   
   
9. In a statement shared with Becker's, an Aetna spokesperson said the company "respectfully disagrees with the conclusions" of the OIG's audit. 
   
   
10. The watchdog applied "high specific targeting" to identify samples audited, the Aetna spokesperson said. "In fact, OIG recognizes that its audit was not designed to analyze the company's overall compliance with federal regulations. We are proud of the strength of our compliance programs," the spokesperson said.