California seeing more workers comp medical review decision letters

The number of Independent Medical Review decision letters is on the rise after several years of steady decreases, according to the California Workers’ Compensation Institute.

Despite the increase, CWCI said, the IMR process continues to uphold utilization review decisions to deny or modify treatment requests nearly 90% of the time.

IMR disputes increased each year after the administrative process for appealing a denial of recommended treatment, created with the SB 863 reforms, was introduced in 2013.

In 2018, Maximus Federal Services issued a record 184,735 IMR decision letters. The total declined each year thereafter, bottoming out at 127,215 in 2022.

“The latest data show that the number of IMR decision letters is now on the rise again, climbing 2.9% in 2023 and 8.2% in 2024, while initial 2025 data show the trend accelerating, with 38,393 letters in the first quarter, up 13% from the same period last year and the highest first quarter output since 2019,” CWCI said in Bulletin 25-09.

Prescription drugs were the most commonly disputed service, representing 30.6% of all IMRs in the first quarter of this year. Physical therapy ranked second, at 13.6%, followed by disputes over injections, at 12.9%. Disputes involving durable medical equipment, prosthetics, orthotics and supplies made up 9.7% of IMRs.

“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% in 2024,” CWCI said. “As in the past, uphold rates varied by type of service, ranging from 77.4% for evaluation/management services to 92.9% for acupuncture.”

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