Press Release


Bob Young

For Release:

February 18, 2016

CWCI Study Spotlights California WC 2015 Independent Medical Review Outcomes

A new CWCI study provides an updated look at California workers’ compensation independent medical review (IMR) decisions rendered in 2015 and finds that even though IMR physicians continue to uphold the vast majority of utilization review (UR) physicians’ denials or modifications of treatment, total IMR volume rose 19% last year.

The Institute’s latest analysis uses data from all 163,826 IMR determination letters issued in 2015 in response to applications submitted to the state after a utilization review (UR) physician modified or denied a requested medical service. Although state lawmakers who enacted IMR expected that the number of disputed treatment requests would decline as doctors, attorneys and others involved in the process became familiar with the types of services that would meet the evidence-based medicine standards and be approved through UR and IMR, the latest data show that after 2 years, IMR volume remains high, with 26,065 more cases in 2015 than in 2014.

CWCI’s review of the 2015 IMR decisions reveals the IMR physicians upheld the UR doctor’s modification or denial of the service 88.6% of the time, just shy of the 91% uphold rate for 2014. The mix of services reviewed by IMR physicians was also similar, with prescription drug requests accounting for half of last year’s IMR decisions, versus 48% in 2014, and the UR determination was upheld in nearly 90% of those pharmaceutical IMRs. Disputes over prescription drugs, physical therapy, durable medical equipment, injections and MRI/CT/PET scans accounted for 75% of all services that went through IMR in 2015, while surgery requests accounted for 4.2%, which was down from 4.7% in 2014. Uphold rates ranged from 80% to 90% for most services, with the exception being Evaluation and Management services - primarily requested referrals for consultations - where nearly 1/3 of the UR modifications or denials were overturned by the IMR physician.

The analysis also linked most of the disputed medical services that went through IMR to a small number of requesting physicians. The top 10% of physicians named in 2015 IMR decision letters (1,276 physicians) accounted for 85% of the disputed service requests, while the top 1% (128 providers) accounted for 46%. As in 2014, the new results also show significant geographic variation, with 34% of the IMR decision letters addressed to Los Angeles County recipients even though only 22% of all claims came from that region. On the flip side, the percentage of IMR decisions was disproportionately low in rural areas of the state, as well as in the Inland Empire, Orange County and San Diego.  

CWCI has published its complete analysis of 2015 IMR outcomes in a Spotlight Report, “Independent Medical Review Decisions: January Through December 2015.” CWCI members and subscribers can download the report and a summary Bulletin at, while others can purchase a copy for $24 at