Reports on Massachusetts Acute Hospital Case Mix Database

Massachusetts Acute Care Hospital
Case Mix Reporting

Under state law, CHIA maintains a database of stay-level encounters with acute care hospitals going back more than 20 years. Collectively known as Case Mix, the databases capture each inpatient admission, emergency department visit, and outpatient observation stay at acute care hospitals in Massachusetts. Case Mix captures the medical reason for the visit, procedures and services provided, charges incurred, and duration of the visit, as well as patient demographics.

CHIA has launched a new report series providing analyses and trends sourced from the Case Mix database.

  • Massachusetts Acute Care Hospital Inpatient Discharge Data offers insights into hospital inpatient utilization patterns, including key measures of utilization overall and by hospital, patient, and discharge characteristics. The latest annual report in this series, published in December 2022, presents analyses using final data over a six-year period, from FFY 2016 to FFY 2021 (October 1, 2015 to September 30, 2021). Additionally, interim updates using preliminary data continue to be published on a quarterly basis via an interactive dashboard, including topics covered in the annual report as well as additional analyses on behavioral health and COVID-19. The current dashboard covers data through FFY 2023 Q4 (through December 2023).



These ongoing series of reports establish an important baseline of hospital utilization that can be used for public health initiatives, analyses of preventable hospitalizations and readmissions, and comparative cost and outcomes research.

For further information about the Massachusetts Acute Hospital Case Mix Database (Case Mix), including information about data governance, data submissions, data enhancements, and use cases, please see the Overview of the Massachusetts Acute Hospital Case Mix Database (December 2019).