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A new California Workers’ Compensation Institute study on the Independent Medical Review process used to resolve California workers’ comp medical disputes shows that after climbing to a record high in 2018, the number of IMR decision letters declined in both 2019 and 2020, falling to an all-time low last year.

The CWCI study is based on a review of more than 1.1 million IMR decision letters issued from 2014 through 2020.

The study notes that the number of IMR determination letters increased from 143,983 in 2014 to a record 184,735 in 2018, but then declined by 26% over the next two years, falling to 163,899 letters in 2019 and 136,746 letters in 2020.

That decline coincided with the implementation of the Prescription Drug Formulary, which as of 2018, established categories of drugs that were Exempt from prospective UR, Non-Exempt (or subject to prospective UR), or Not Listed, as well as subcategories of Non-Exempt drugs (Special Fill and Perioperative drugs) to allow for special circumstances or pre- and post-operative situations in which physicians can prescribe limited amounts of certain drugs that would otherwise be subject to prospective UR and IMR.

At that point, prescription drug disputes accounted for 46.4% of all IMRs, but within a year, that percentage was down to 41.1%, and in 2020 it fell to 39.1%.

Since 2018, opioids’ share of the pharmaceutical IMRs have declined from 32.2% to 28.3%, while over the same two-year span the biggest increase has been in dermatologicals, which have jumped from 10.9% to 14.8% of the pharmaceutical IMRs. With prescription drugs accounting for a declining share of the IMR disputes since 2018, the study noted a shift in the mix of services submitted for IMR, with physical therapy; injections; and durable medical equipment, prosthetics, orthotics and supplies (DMEPOS) all seeing their share of the IMRs increase by 1.5 to 2.0 percentage points over the past two years.

The study notes that last year’s decline in IMR volume was also spurred on by the pandemic, as the number of job injury claims declined as California’s unemployment rate spiked from 5.5% in March to 16.4% in April and millions of Californians began to work from home.

The impact on IMR volume was immediate, as a comparison of monthly IMR determinations from 2019 and 2020 shows a similar number of IMRs in March of each year, but in April 2020 there were 1,762 fewer IMRs than in April 2019, while the differential was 5,387 fewer IMRs in May; 3,666 fewer IMRs in June; 2,841 fewer IMRs in July; and 3,848 fewer IMRs in August. IMR volume was down across all regions of the state last year, with the biggest decline occurring in Los Angeles County, which had about 9,400 fewer IMR determination letters in 2020 than in 2019.

As in prior studies, the latest results show that a small number of physicians continue to drive much of the IMR activity, with the top 1% of requesting physicians (89 doctors) accounting for 39.8% of the disputed service requests that underwent IMR in 2020. The top 10 individual physicians alone accounting for 10.2% of the disputed requests, and the study found that seven of the top 10 physicians in 2020 were also on the top 10 list for 2019.

IMR outcomes were fairly stable as IMR physicians upheld the UR doctors’ modification or denial of services 89.4% of the time last year, compared to 88.2% of the time in 2019. Uphold rates broken out by the type of medical service request ranged from 80.7% for evaluation/management services to 91.3% for DMEPOS and injections.

CWCI has released its latest IMR analysis as a Research Update Report, “Independent Medical Review Decisions: January 2014 Through December 2020.”