Cigna AI System PXDX Rejected 300,000 Health Insurance Claims in Two Months

In March and April 2022, Cigna Healthcare deployed an AI system called PXDX (PxDx Medical Management System) to review and reject health insurance claims at an unprecedented scale and speed. According to internal company data obtained by ProPublica, the system flagged over 300,000 claims for denial during this two-month period, with the company's physicians spending an average of only 1.2 seconds reviewing each claim before approving the AI's denial recommendation. The PXDX system was designed to identify claims that could be denied based on various criteria, but the investigation revealed that physicians were essentially rubber-stamping the AI's decisions without conducting meaningful medical reviews. Internal Cigna documents showed that some physicians were approving denials for hundreds of claims per hour, making it impossible to conduct the thorough medical evaluation required by state insurance laws and professional standards. The rapid-fire denials affected patients across multiple states who had submitted claims for various medical services including diagnostic tests, procedures, and treatments. Many patients were forced to pay out-of-pocket for covered services or navigate lengthy appeals processes to overturn the denials. The scale and speed of denials was unprecedented in the health insurance industry, raising serious questions about whether meaningful medical review was occurring. Following ProPublica's investigation published in March 2023, multiple class action lawsuits were filed against Cigna alleging that the company violated state laws requiring physicians to conduct meaningful medical reviews before denying claims. The lawsuits argue that the 1.2-second average review time demonstrates that no genuine medical evaluation was taking place, effectively delegating medical decisions to an algorithm in violation of insurance regulations. The incident highlighted broader concerns about the use of AI in healthcare decision-making and the adequacy of human oversight in automated systems that directly impact patient care and access to medical services. Industry experts noted that while AI can assist in claims processing, the speed and scale of Cigna's denials suggested an over-reliance on automated decisions without proper medical supervision.