Press Release


Bob Young

For Release:

November 10, 2020

CWCI Analyzes California Workers' Comp Hospital Stays From 2010 to 2019

Oakland, CA – A new study from the California Workers’ Compensation Institute (CWCI) shows the steep drop in the number of inpatient hospitalizations involving California injured workers over the past decade was largely due to the ongoing decline in spinal fusions and a more recent decline in lower extremity joint surgeries. 

 The study reviews discharge data compiled by the state Office of Statewide Health Planning and Development (OSHPD) on 35.9 million inpatient hospital stays from 2010 through 2019 paid by workers’ compensation, Medicare, Medi-Cal and private insurance, in order to identify workers’ compensation inpatient trends and to compare the volume and types of California inpatient hospitalizations covered by workers’ compensation to those covered by the three other systems.  Workers’ comp is by far the smallest of the medical delivery systems reviewed, accounting for just 0.4 percent of all inpatient stays in 2019, which is not surprising given that it has only accounted for between 1.4 percent and 1.6 percent of California healthcare costs over the past decade.  However, over the same 10-year span the study found that the number of workers’ comp inpatient hospitalizations declined 36.2 percent, more than twice the 15.9 percent decline noted for private coverage, and in sharp contrast to the 4.0 percent increase in Medicare and the 14.5 percent increase in Medi-Cal hospitalizations.  The study found that a key factor leading to the reduction of workers’ comp inpatient stays was the sharp decline in the number of injured workers receiving spinal fusions, which fell 53.1 percent between 2010 and 2019, a decline that was spurred by multiple factors including the adoption of utilization review and independent medical review programs requiring that treatment meet evidence-based medicine standards, the elimination of duplicate payments for implantable devices used in spinal surgeries, and fraud convictions that led to the sale of hospitals that had a high volume of workers’ comp back surgeries.  At the same time the overall number of work injury claims declined and there were technological and procedural advances that allowed more services to be provided in outpatient settings, prompting the growth of ambulatory surgery centers and an expansion of services at those facilities.  The study notes that spinal fusions were not the only type of workers’ compensation inpatient hospitalizations that saw a significant decline, as the number of workers’ comp discharges associated with lower extremity joint replacements has gradually declined in each of the past five years, falling from 2,727 workers’ comp discharges in 2014 to 2,140 in 2019, a net decrease of 21.5 percent.

In addition to tracking inpatient trends for California workers’ compensation, Medicare, Medi-Cal and private plans over the 10-year study period, the study also provides detailed data showing the breakdown of workers’ comp inpatient stays among the top 5 Major Diagnostic Categories (MDCs); the proportion of surgical vs. “medical” (non-surgical) hospitalizations in each of the 4 payer groups; the top 5 workers’ comp surgical and medical inpatient discharges by diagnostic-related group (MS-DRG) in 2019; the breakdown of the top 10 workers’ comp MS-DRGs across payer groups in 2019; the volume and prevalence of spinal fusion surgeries by payer group from 2010 through 2019; and the top 10 hospitals for workers’ comp inpatient care as well as the 10 hospitals with the highest ratio of workers’ compensation inpatients to total inpatients.

CWCI has issued its study as a Research Update report, “California Workers’ Compensation Inpatient Hospitalization Trends, 2010-2019.”  CWCI members and subscribers can access the report in the Research section at and others can purchase it for $14 from the online Store.  CWCI members may also  log in to the Research section to access an updated version of CWCI’s Inpatient Hospitalization Claim Interactive Tool.