Oakland, CA – After three years of increases, California workers’ compensation Independent Medical Reviews (IMRs), used to resolve California workers’ compensation medical disputes, edged down in the first nine months of 2026 according to the California Workers’ Compensation Institute (CWCI). CWCI’s latest review of state data found that pharmaceutical disputes continued to generate the largest share of IMR decisions and that IMR physicians upheld 90.2% of all utilization review (UR) physician denials and modifications they reviewed.

     CWCI’s review encompassed about 1.8 million IMR decision letters issued from 2015 through September of this year. It found that 110,965 letters were issued in the first three quarters of 2026, down 3.1% from the same period last year, the first reduction since IMR volume began rebounding from a historic low in 2022. Despite the drop, the latest tally remained well above the comparable nine-month totals for 2020 through 2024.

     The overall IMR uphold rate for UR denials and modifications rose to 90.2%, up from 89.8% in 2025, remaining within the relatively narrow range recorded since 2015. Uphold rates varied by medical service category, ranging from 80.8% for Evaluation and Management requests to 95.2% for Acupuncture. The largest increases occurred in Surgery, where the uphold rate climbed from 86.1% to 88.8%, and Psychiatric Services, where the rate rose from 81.3% to 83.1%. Pharmaceutical requests continued to account for more IMR disputes than any other service category, representing 30.8% of all IMR decisions, slightly above the 30.5% share in 2025. Physical Therapy ranked second with 13.2% of the decisions, followed by Injections at 12.8%.

     Among the pharmaceutical IMRs, opioid disputes continued to decline, falling to just 16.7% of all prescription drug decisions, as the uphold rate for opioid denials and modifications hit an all-time high of 95.7%. At the same time, dermatological drugs accounted for a record 25.9% of the pharmaceutical IMRs, more than double their 12.3% share in 2018. Musculoskeletal drugs ranked second at 20.0% and had the highest uphold rate among drug categories at 98.5%. Anticonvulsants also reached a record share, increasing to 10.6% of the pharmaceutical IMRs.

     CWCI’s review also noted the continued concentration of IMR activity among a relatively small group of physicians. The top 10% of physicians named in decision letters during the 12 months ending September 2026 (789 providers) accounted for 84.5% of all disputed service requests and the top 1% (79 providers) accounted for 41.9%. The data also show that just 10 individual physicians were associated with 10.4% of the disputed service requests decided by IMR. The uphold rate for UR denials and modifications involving those 10 physicians was 90.3%.

     CWCI will continue monitoring IMR activity and publish full-year 2026 results when available. In the meantime, Institute members can access 10 slides with detailed IMR statistics from 2015 through September 2026 by logging on to www.cwci.org⁠ and selecting Independent Medical Review under the Research tab.

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