Federal Auditors Find Most Sampled Medicare Advantage Diagnosis Codes From Gateway Health Plan Lacked Medical Record Support

The Department of Health and Human Services Office of Inspector General released a compliance audit of Gateway Health Plan, a Medicare Advantage organization operating under contract H5932, as part of a continuing series examining whether plans accurately submit diagnosis codes to CMS for risk adjustment.

For 232 of 286 sampled enrollee-years, medical records did not support the diagnosis codes submitted, resulting in 830,334 dollars in net overpayments from the sample reviewed. The OIG recommended that Gateway refund estimated overpayments to the federal government and improve internal procedures for preventing and detecting high-risk miscoding.

The risk adjustment system uses diagnosis codes submitted by plans to set monthly payments from CMS to each Medicare Advantage organization. When codes are not supported by clinical documentation, the resulting payments exceed what the program would otherwise pay, drawing down Medicare Trust Fund resources.

CMS acknowledged the findings and indicated it would pursue repayment through standard audit reconciliation. Gateway was encouraged to review its compliance procedures for the specific high-risk diagnosis categories that auditors flagged.

This individual-plan audit is part of a broad OIG initiative covering dozens of Medicare Advantage insurers. Aggregate overpayments linked to unsupported diagnosis codes across all plans have been estimated in prior government reports at tens of billions of dollars annually across the program.