CHIA Reports on Hospital Emergency Department Data

DATE : September 16, 2021

CHIA has published a new report that offers insights into emergency department (ED) utilization patterns in the period leading up to the outbreak of COVID-19. Massachusetts Acute Care Hospital Emergency Department Data (FFY 2016-2019) presents key measures of ED utilization overall and by hospital, patient, and visit characteristics from FFY 2016 to FFY 2019.


  • In FFY 2019, there were over 3.1 million ED visits in the Commonwealth. 


  • Medicaid was the most common expected payer type (31.8%); Medicaid and Medicare together were the expected primary payer type for a majority of ED visits (60.0%). 


  • ED visits with behavioral health primary diagnoses were nearly twice as common among Medicaid patients as among Medicare and commercially insured patients (11.3%, 6.1%, 6.6%, respectively). 


  • Patients with a history of frequent ED use represented 1.2% of ED patients and accounted for 9.4% of all ED visits. 


  • Over 32% of treat-and-release visits lasted more than four hours; this was twice as common among treat-and-release visits with a behavioral health primary diagnosis.



This is the first annual statewide report on ED utilization and part of a new reporting series providing analyses on patterns and trends of acute care hospital services from CHIA’s Case Mix database. In addition to this report, CHIA has published a parallel report on inpatient visits in Massachusetts in December 2020 and is currently developing a report on outpatient observation visits in the Commonwealth. In the future, CHIA will produce data updates on a regular basis for all three settings of care to provide timely access to key analyses from these data as they are submitted and processed by the agency.

This report is also accompanied by a databook and technical appendix.

 eBlast Case Mix EDD Eblast graphic 091621 v2