CWCI Finds California Workers' Comp Independent Medical Reviews Are Trending Up

Business Wire

26-06-2025

BUSINESS WIRE)--After declining steadily from 2018 through 2022, the number of Independent Medical Review (IMR) decision letters issued in response to California workers' comp medical disputes is now trending up, increasing in 2023, 2024, and the first quarter of 2025 according to the California Workers' Compensation Institute (CWCI), but the uphold rate for medical service modifications and denials that are reviewed remains close to 90%.
After declining from 2018 - 2022, California workers' comp Independent Medical Reviews are on the rise, and new data show the trend accelerating.
CWCI's latest review of IMR activity and outcomes examined 1.57 million IMR decision letters issued from 2015 through March of this year in response to applications submitted to the state after a Utilization Review (UR) physician modified or denied a workers' comp medical service request. As in prior reviews, CWCI tracked the number of letters issued each quarter; determined the distribution and uphold rates for disputed treatment requests by type of medical service (and the distribution and outcomes of pharmaceutical IMRs by major drug group); measured IMR response times; and calculated the percentage of IMRs associated with high-volume physicians.
IMR, introduced in 2013, was expected to reduce medical disputes by helping to ensure that workers' comp treatment met evidence-based medicine standards, but it was not until 2019 that the number of IMR disputes began a steady decline, with the number of IMR decision letters falling by 31% from the peak level of 184,385 in 2018 to 127,215 in 2022. That decline coincided with a reduction in the number of job injury claims during the pandemic and a drop in the number of pharmaceutical disputes after the state added Pain Management and Opioid Guidelines to its Medical Treatment Utilization Schedule (MTUS) in late 2017 and adopted the MTUS Drug Formulary in January 2018. More recent data, however, show IMR letter volume rose 2.9% in 2023 and 8.2% in 2024, and initial results for this year show the trend accelerating, with 38,393 IMR decision letters in the first 3 months of 2025, 13% more than in the same period last year. Even with the increase in IMR volume, the median IMR response time (from receipt of the application to the date of the decision letter) was 32 days in 2024, the same as in 2022. Furthermore, 25% of the letters were issued within 28 days, and 75% were issued within 38 days, all within the time allotted to the state's Independent Medical Review Organization to confirm the eligibility of the application; request, receive, and process medical records; assign the case to a physician reviewer; and issue a decision.
Disputes over prescription drug requests represented 30.6% of all IMRs in the first quarter of this year – more than any other type of medical service, but down from 33.4% in 2024 and 50.7% in 2015. Much of that decline was due to the reduction in IMRs involving opioid requests, which dropped from 32% of all pharmaceutical IMRs in 2018 to 18.6% in the first quarter of this year. With prescription drugs representing a declining share of the IMR disputes, the percentage of IMRs involving disputes over other medical services has increased, with physical therapy disputes accounting for 13.6% of IMRs in the first quarter of 2025, injection disputes accounting for 12.9%, and disputes over durable medical equipment, prosthetics, orthotics and supplies accounting for 9.7%.
A small number of physicians continue to drive much of the IMR activity, as the top 1% of requesting physicians (81 doctors) accounted for 42.2% of the disputed service requests that underwent IMR in the 12 months ending on March 30 of this year, and the top 10 individual physicians accounted for 10.9% of the disputed requests. CWCI found that 7 of the providers on the latest top 10 list were also on the top 10 list the prior year.
IMR outcomes remain stable, as IMR physicians upheld 89.1% of UR doctors' treatment modifications or denials in the first quarter of 2025 compared to 88.0% in 2024. As in the past, uphold rates varied by type of service, ranging from 77.4% for evaluation/management services to 92.9% for acupuncture.
CWCI members and subscribers will find a more detailed summary of IMR experience through March 2025 in Bulletin 25-09 at www.cwci.org. Institute members can also access updated IMR slides under the Research tab.