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CWCI Study Finds California Workers’ Comp IMR Volume May Be Leveling Off

September 21, 2017 (2 min read)

Oakland – A new study on the California workers’ compensation independent medical review (IMR) process established by state lawmakers to resolve medical disputes finds that in the first half of this year, more than 91% of  all utilization review (UR) physicians’ modifications or denials of treatment  that were reviewed by an IMR physician were upheld , and after increasing steadily since 2013, IMR volume appears to be leveling off.  

California law requires workers’ comp claims administrators to have a Utilization Review (UR) program to assure that care provided to injured workers is backed by clinical evidence outlined in medical guidelines adopted by the state.  Most treatment requests are approved by UR, but in 2012 state lawmakers adopted IMR to give injured workers a chance to get an independent medical opinion on treatment requests that UR physicians deny or modify.  Use of IMR has grown sharply since 2013, but in its new study, the California Workers’ Compensation Institute (CWCI) tallied 86,066 IMR decision letters issued in the first half of this year in response to applications submitted to the state after a UR physician modified or denied a medical service request. At that rate, the volume of IMR letters in 2017 will decline 2.2% from the 2016 level, while the number of individual treatment requests decided in those letters will be down 0.6 percent – the first time IMR volume has not increased since the process took effect in 2013. 

CWCI’s analysis of the 2017 IMR decisions found that after reviewing the patient’s records and other information provided to support the request, IMR physicians upheld the UR doctor’s modification or denial of the service 91.3% of the time, which was virtually identical to the 91.2% uphold rate in 2016.  As in prior years, pharmaceutical requests accounted for almost half of the 2017 IMR decisions, led by opioids, which represented 28.8% of all 2017 prescription drug IMRs, even though IMR doctors have consistently upheld the UR decision in 90% of the opioid requests. Requests for physical therapy; injections, durable medical equipment; and MRIs, CTs and PET scans together comprised another 29% of the 2017 IMRs, but no other medical service category accounted for more than 4% of the disputed requests. Among the various service categories, uphold rates in 2017 ranged from 80.4% for evaluation/management services (primarily consultations) to 94.6% for chiropractic manipulation.

The Institute study also confirmed that a relatively small number of physicians continue to account for most of the disputed medical services that go through IMR. A breakdown of IMR volume among high-volume physicians showed that the top 10% of physicians who were named in IMR decision letters issued between July 2016 and June 2017 (1,114 doctors) accounted for 85% of the disputed service requests during that period, while the top 1% (111 providers) accounted for 45% of the disputed services.

Additional details and graphics from the study are available in a CWCI Spotlight Report, “Independent Medical Review Decisions: January 2014 Through June 2017,” which CWCI members and subscribers can access at and others can purchase from the CWCI store at