Press Release


Bob Young

For Release:

October 29, 2021

CWCI: California WC Hospital Stays Decline as COVID Affects the Quantity and Types of Admissions

Oakland, CA – The latest update to California Workers’ Compensation Institute (CWCI) research on California workers’ compensation inpatient hospital stays shows the number of injured worker hospitalizations fell 17.2 percent in 2020 – the first year of the COVID-19 pandemic -- bringing the total decline since 2010 to 47.2 percent.  

Using hospital discharge data compiled by the California Office of Statewide Health Planning and Development (OSHPD) on nearly 39.2 million 2010 through 2020 inpatient stays, CWCI measured and compared the volume and types of California inpatient hospitalizations paid under workers’ compensation to those paid by Medicare, Medi-Cal and private coverage.  Since 2010, the number of inpatient discharges in the state has declined steadily for each of the four payer groups studied except Medi-Cal, where enrollment and the number of hospitalizations surged following enactment of the Affordable Care Act in 2014.  Throughout the 11-year study period, workers’ compensation has consistently represented the smallest share of the hospital stays, with injured workers accounting for just 0.4 percent of inpatient discharges in each of the past four years, compared to 0.5 percent from 2014 to 2016, and 0.6 percent from 2010 to 2013.  Prior CWCI studies noted that several factors contributed to the decline in workers’ comp inpatient stays from 2010 to 2019, including fluctuations in the number and types of claims; the adoption of utilization review and independent medical review programs requiring that treatment meet evidence-based medicine standards; and a reduction in the number of spinal fusions.  The latest study also highlights the significant impact of the COVID-19 pandemic on workers’ compensation inpatient care, including a 20% decline in surgical admissions and a 10% decline in non-surgical (Medical) admissions; a surge in hospitalizations for diseases and disorders of the respiratory system (which went from 2.6% of all injured worker discharges in 2019 to 7.4% in 2020); and a growing percentage of hospital stays for septicemia and sepsis, which are linked to severe COVID infections and which increased from 3.3% to 5.2% of the workers’ compensation hospitalizations last year.

Drilling down further, the new report also provides analyses and exhibits detailing:

  • The breakdown of workers’ comp inpatient stays among the top five Major Diagnostic Categories (MDCs);
  • The proportion of surgical vs. “medical” (non-surgical) hospitalizations in each of the four payer groups;
  • The top five surgical and medical inpatient discharges by diagnostic-related group (MS-DRG) in 2020;
  • The breakdown of the top 10 workers’ comp MS-DRGs across payer groups in 2020;
  • The volume and prevalence of spinal fusion surgeries by payer group from 2010 through 2020; and
  • The top ten hospitals based on the percentage of their inpatient discharges covered by workers’ comp, and the proportion of California workers’ comp medical and surgical hospitalizations rendered at those facilities.

CWCI has published its study in a Research Update report, “California Workers’ Comp Inpatient Hospitalization Trends, 2010-2020,” which Institute members and subscribers can access in the Research section at and others can purchase for $14 from CWCI’s online Store