Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Beta This is a new resource - your feedback will help us improve it.

Series: Medicare Part C Audits of Documentation Supporting Specific Diagnosis Codes

Announced on  | Last Modified on  | Series Number: SRS-A-25-017
Status
Active
Agency
Centers for Medicare and Medicaid Services

OBJECTIVE

Payments to Medicare Advantage (MA) organizations are risk-adjusted based on each enrollee's health status (SSA § 1853(a)). MA organizations are required to submit risk-adjustment data to CMS in accordance with CMS instructions (42 CFR § 422.310(b)), and inaccurate diagnoses may cause CMS to pay MA organizations improper amounts. In general, MA organizations receive higher payments for enrollees with more complex diagnoses. CMS estimates that 9.5 percent of payments to MA organizations are improper, mainly due to unsupported diagnoses submitted by MA organizations. Prior OIG reviews have shown that some diagnoses are more at risk than others to be unsupported by medical record documentation. We will perform a targeted review of these diagnoses and will review the medical record documentation to ensure that it supports the diagnoses that MA organizations submitted to CMS for use in CMS's risk score calculations and to determine whether the diagnoses submitted complied with Federal requirements.

There are 5 projects in this series.

Project titles will remain unpublished until projects are complete and reports are posted.

ACTIVE PROJECTS IN THIS SERIES (2)

Project A-06-24-05002 • Announced on Jan 29, 2024

Project A-02-24-01019 • Announced on Sep 11, 2024

COMPLETED PROJECTS IN THIS SERIES (3)

Medicare Advantage Compliance Audit of Specific Diagnosis Codes that United Healthcare Benefits of Texas, Inc., Contract (H0609) Submitted to CMS

Project A-07-24-01215 • Completed on September 23, 2026

Medicare Advantage Compliance Audit of Specific Diagnosis Codes That HumanaChoice (Contract H5216) Submitted to CMS

Project A-05-24-00010 • Completed on September 10, 2026

Medicare Advantage Compliance Audit of Specific Diagnosis Codes That UnitedHealthcare of Wisconsin, Inc. (Contract H5253) Submitted to CMS

Project A-07-24-01214 • Completed on September 10, 2026

TIMELINE

  • October 3, 2023
    Series Number SRS-A-25-017 Assigned
  • October 3, 2023
    Projects Announced

    Medicare Advantage Compliance Audit of Specific Diagnosis Codes That UnitedHealthcare of Wisconsin, Inc. (Contract H5253) Submitted to CMS - A-07-24-01214

  • Medicare Advantage Compliance Audit of Specific Diagnosis Codes that United Healthcare Benefits of Texas, Inc., Contract (H0609) Submitted to CMS - A-07-24-01215

  • January 29, 2024
    Project Announced

    Project A-06-24-05002

  • January 30, 2024
    Project Announced

    Medicare Advantage Compliance Audit of Specific Diagnosis Codes That HumanaChoice (Contract H5216) Submitted to CMS - A-05-24-00010

  • September 11, 2024
    Project Announced

    Project A-02-24-01019

  • September 10, 2026
    Project Complete - A-05-24-00010

    Medicare Advantage Compliance Audit of Specific Diagnosis Codes That HumanaChoice (Contract H5216) Submitted to CMS complete. This audit resulted in 4 recommendations.

  • September 10, 2026
    Project Complete - A-07-24-01214

    Medicare Advantage Compliance Audit of Specific Diagnosis Codes That UnitedHealthcare of Wisconsin, Inc. (Contract H5253) Submitted to CMS complete. This audit resulted in 4 recommendations.

  • September 23, 2026
    Project Complete - A-07-24-01215

    Medicare Advantage Compliance Audit of Specific Diagnosis Codes that United Healthcare Benefits of Texas, Inc., Contract (H0609) Submitted to CMS complete. This audit resulted in 4 recommendations.

  • Today
    2 Audits In-Progress
  • Est FY2027
    Estimated Fiscal Year for Series Completion

3 REPORT PUBLISHED

Medicare Advantage Compliance Audit of Specific Diagnosis Codes That HumanaChoice (Contract H5216) Submitted to CMS (A-05-24-00010)

Most of the selected diagnosis codes that HumanaChoice submitted to CMS for use in CMS’s risk adjustment program did not comply with Federal requirements.

  • For 178 of the 220 sampled enrollee-years, medical records did not support the diagnosis codes and resulted in $669,237 in overpayments.
  • On the basis of our sample results, we estimated that HumanaChoice received at least $130.9 million in overpayments for 2020 and 2021.

As demonstrated by the errors found in our sample, HumanaChoice’s policies and procedures to prevent, detect, and correct noncompliance with CMS’s program requirements could be improved.

26-A-05-103.01 to CMS - Open Unimplemented
Update expected on 03/25/2027
We recommend that Humana, Inc. refund to the Federal Government the $130,922,653 of estimated overpayments.

26-A-05-103.02 to CMS - Open Unimplemented
Update expected on 03/25/2027
We recommend that Humana, Inc. determine, for the 212 enrollee-years that we did not review in the potentially mis-keyed diagnosis code high-risk group, whether the medical records in each case support the diagnosis for the unrelated condition and refund any resulting overpayments to the Federal Government.

26-A-05-103.03 to CMS - Open Unimplemented
Update expected on 03/25/2027
We recommend that Humana, Inc. identify, for the high-risk diagnoses included in this report, similar instances of noncompliance that occurred after our audit period and refund any resulting overpayments to the Federal Government.

26-A-05-103.04 to CMS - Open Unimplemented
Update expected on 03/25/2027
We recommend that Humana, Inc. continue its examination of its existing compliance procedures to identify areas where improvements can be made to ensure that diagnosis codes that are at high risk for being miscoded comply with Federal requirements (when submitted to CMS for use in CMS's risk adjustment program) and take the necessary steps to enhance those procedures.

View in Recommendation Tracker

Medicare Advantage Compliance Audit of Specific Diagnosis Codes That UnitedHealthcare of Wisconsin, Inc. (Contract H5253) Submitted to CMS (A-07-24-01214)

Most of the selected diagnosis codes that United submitted to CMS for use in CMS’s risk adjustment program did not comply with Federal requirements.

  • For 183 of the 250 sampled enrollee-years, medical records did not support the diagnosis codes and resulted in $722,280 in overpayments.
  • On the basis of our sample results, we estimated that United received at least $46.9 million in overpayments for 2020 and 2021.

As demonstrated by the errors found in our sample, United’s policies and procedures to prevent, detect, and correct noncompliance with CMS’s program requirements could be improved.

26-A-07-104.01 to CMS - Open Unimplemented
Update expected on 03/25/2027
We recommend that UnitedHealthcare of Wisconsin, Inc. refund to the Federal Government the $46,913,121 of estimated overpayments.

26-A-07-104.02 to CMS - Open Unimplemented
Update expected on 03/25/2027
We recommend that UnitedHealthcare of Wisconsin, Inc. determine, for the 81 enrollee-years that we did not review in the potentially mis-keyed diagnosis code high-risk group, whether the medical records in each case support the diagnosis for the unrelated condition and refund any resulting overpayments to the Federal Government.

26-A-07-104.03 to CMS - Open Unimplemented
Update expected on 03/25/2027
We recommend that UnitedHealthcare of Wisconsin, Inc. identify, for the high-risk diagnoses included in this report, similar instances of noncompliance that occurred after our audit period and refund any resulting overpayments to the Federal Government.

26-A-07-104.04 to CMS - Open Unimplemented
Update expected on 03/25/2027
We recommend that UnitedHealthcare of Wisconsin, Inc. continue its examination of its existing compliance procedures to identify areas where improvements can be made to ensure that diagnosis codes that are at high risk for being miscoded comply with Federal requirements (when submitted to CMS for use in CMS's risk adjustment program) and take the necessary steps to enhance those procedures.

View in Recommendation Tracker

Medicare Advantage Compliance Audit of Specific Diagnosis Codes That UnitedHealthcare Benefits of Texas, Inc. (Contract H0609), Submitted to CMS (A-07-24-01215)

Most of the selected diagnosis codes that United submitted to CMS for use in CMS’s risk adjustment program did not comply with Federal requirements.

  • For 172 of the 230 sampled enrollee-years, medical records did not support the diagnosis codes and resulted in $622,927 in overpayments.
  • On the basis of our sample results, we estimated that United received at least $24.4 million in overpayments for 2020 and 2021.

As demonstrated by the errors found in our sample, United’s policies and procedures to prevent, detect, and correct noncompliance with CMS’s program requirements could be improved.

26-A-07-115.01 to CMS - Open Unimplemented
Update expected on 04/15/2027
We recommend that UnitedHealthcare Benefits of Texas, Inc. refund to the Federal Government the $24,465,369 of estimated overpayments.

26-A-07-115.02 to CMS - Open Unimplemented
Update expected on 04/15/2027
We recommend that UnitedHealthcare Benefits of Texas, Inc. determine, for the 26 enrollee-years that we did not review in the potentially mis-keyed diagnosis code high-risk group, whether the medical records in each case support the diagnosis for the unrelated condition and refund any resulting overpayments to the Federal Government.

26-A-07-115.03 to CMS - Open Unimplemented
Update expected on 04/15/2027
We recommend that UnitedHealthcare Benefits of Texas, Inc. identify, for the high-risk diagnoses included in this report, similar instances of noncompliance that occurred after our audit period and refund any resulting overpayments to the Federal Government.

26-A-07-115.04 to CMS - Open Unimplemented
Update expected on 04/15/2027
We recommend that UnitedHealthcare Benefits of Texas, Inc. continue its examination of its existing compliance procedures to identify areas where improvements can be made to ensure that diagnosis codes that are at high risk for being miscoded comply with Federal requirements (when submitted to CMS for use in CMS's risk adjustment program) and take the necessary steps to enhance those procedures.

View in Recommendation Tracker
Work Plan Type
Office of Audit Services
HHS Agencies
Centers for Medicare and Medicaid Services
Issue Areas
OIG Statutory Authority and Regulatory Matters Departmental Operational Issues Managed Care Financial Stewardship
Target Groups
Elderly
Financial Groups
Medicare C