Two critical indicators of hospital quality are rates of mortality and readmission. They show how well hospitals keep patients alive and healthy.
A national source for these measures is the Centers for Medicare & Medicaid Services, which collects hospital mortality and readmission data for fee-for-service Medicare patients ages 65 and older.
Like other quality metrics, mortality and readmission measures drive quality improvement and inform consumers where to seek care.
They can also be a rich source of stories — such as examining the performance of a specific hospital or revealing industry trends like the impact of staffing issues on quality of care.
This tip sheet explains how to use mortality and readmission measures in your reporting and goes over recent changes in how data are collected and calculated. It draws from a variety of sources including previous AHCJ articles, CMS documents and health policy literature.
How long have these measures been around?
CMS began publicly reporting mortality in 2007 for two conditions: acute myocardial infarction and heart failure. Mortality measures have since expanded to chronic obstructive pulmonary disease, pneumonia and stroke. CMS has also created a hospital-wide mortality measure.
The Hospital Readmission Reduction Program launched in 2012 to penalize hospitals for excess readmissions for heart failure, acute myocardial infarction, and pneumonia. Measures in the program expanded to chronic obstructive pulmonary disease (COPD), coronary artery bypass graft (CABG), and hip and knee replacement. A hospital-wide readmission measure has also been added.
What do the measures show?
CMS’s mortality measures show the rate at which patients die of any cause within 30 days of being admitted (hospice patients are excluded from mortality measures).
Readmission measures show the rate at which patients are readmitted to a hospital for any reason within 30 days of discharge.
All are based on three years of data, which enables a more precise estimate of a hospital’s true rate and reduces the impact of random fluctuations that can occur with a single year of data.
For accurate comparisons across hospitals, measures are adjusted to account for factors that can influence a patient’s outcome such as age, sex, comorbidities, and severity of illness. These modified figures are called risk-standardized mortality rates and risk-standardized readmission rates.
How does CMS categorize a hospital’s performance?
In addition to a calculated rate for each measure, CMS indicates whether a hospital performs lower (better) than the national rate, no different than the national rate, or higher (worse) than the national rate.
You may wonder why CMS gives lower and upper estimates. Those numbers represent a range of values within which we can be 95% confident that the true value lies.
The agency avoids reporting and categorizing a rate if a hospital has less than 25 relevant cases.
Why are these measures meaningful?
Mortality rates reflect major aspects of care that affect patient outcomes, such as preventing and responding to complications, providing timely care, and adhering to safety protocols.
Readmission measures indicate how well hospitals execute critical tasks such as discharge planning, instructions to patients and their families, and follow-up care.
In addition to spurring improvement in targeted areas, these measures can have spillover effects for other conditions and patient groups. For example, some research suggests that the Hospital Readmission Reduction Program measures reduced readmissions for patients with colon cancer as well as for non-Medicare patients.
How does CMS use these measures?
Mortality and readmission factor heavily in CMS’s star ratings for hospitals, which guide consumer choices on where to seek care.
In addition to the readmission reduction program, these measures are used in CMS’s Hospital Value-Based Purchasing Program, which gives hospitals incentive payments for high-quality care, and the Inpatient Quality Reporting Program, which promotes transparency.
Relatedly, hospitals sometimes use good performance as leverage in negotiations with insurance companies.
How timely are these measures?
There is always a significant lag in public release, which typically happens every quarter. For example, the most recent reports that were publicly available at the time of this writing, in December 2023, reflect data for July 2019 through June 2022.
The lag between data collection and release reduces the usefulness of measures, since they don’t reflect a hospital’s current quality.
How do I look up the performance of a single hospital?
You can look up individual hospitals or compare up to three hospitals using CMS’s Care Compare tool.
- Enter the name of the hospital you are interested in, or search for all hospitals in a city or zip code.
- Select one hospital to examine or compare up to three hospitals by selecting them and clicking the “Compare” command on the far right.
- Scroll down. Mortality and readmission measures are listed under “Payment & value of care” and “Complications & deaths.”
- Each measure shows the hospital’s calculated rate; how it compares to the national rate (better, worse, no different); and the number of patients included in the measure.
How do I examine data across many hospitals?
For measures covering a large number of hospitals, use CMS’s Provider Data Catalog, which has files for hospital, state, and national reporting levels.
To find datasets containing mortality measures, use the search term “complications and deaths.” For readmission measures, use the search term “unplanned hospital visits.”
You can download files to manipulate the data in your own spreadsheet, or use the site’s filters to identify specific providers or measures. Each page has a tab in the upper right corner to view archived data.
What are “hybrid” measures?
CMS has adopted the use of electronic health records as a way to improve the accuracy and ease of reporting.
Recently, it changed its risk-adjustment process for two measures: hospital-wide mortality and hospital-wide readmission. Rather than the old method of using claims data for risk adjustment, new versions of these measures draw data points from electronic health records.
The measures will continue to use claims data on admissions, discharges, procedures and diagnoses. Thus, the measures rely on two data sources, resulting in a “hybrid” approach (for more of an explanation, check out this video that likens hybrid measures to a labradoodle).
These two hybrid measures become mandatory in September 2024, when hospitals will be required to submit data for July 2023 through June 2024.
Why is there data missing for 2020?
CMS waived reporting requirements for the first six months of 2020, saying it wanted to reduce burdens on providers during the COVID pandemic.
Since mortality and readmission measures are usually based on three years of data, that decision creates data gaps for measures reported in 2022, 2023 and 2024. For details, read CMS’s information on data collection periods.
What are some ways to start using these measures?
- Identify hospitals that have exceptionally good or bad performance. Are there hospitals in your region that have poor performance in certain areas of care?
- Compare hospitals with others in the state or nation.
- Filter data by zip code, county or ownership status to identify trends. Are there differences between urban, suburban and rural hospitals? Does ownership status correlate with performance differences?
How can I broaden my research?
Look up other CMS measures such as patient satisfaction collected via the HCAHPS (Hospital Consumer Assessment of Healthcare Providers and Systems) survey and safety indicators such as infection rates. Many are easy to find on Care Compare.
It’s also worth checking whether a hospital has recent inspection reports or has voluntarily submitted quality data to The Leapfrog Group, a payer-funded watchdog.
Then, ask hospital officials for their point of view.
This story broadcast on WHQR Public Media in Wilmington, N.C., used these various data sources to explain why a local hospital received a two-star rating out of five from CMS.
Remember that data go only so far. Don’t forget about human sources, who can explain imperfections in the system.
For example, interviews with nurses, physicians and patients’ family members animated a wrenching NBC story about how HCA Healthcare tried to game the system by pushing critically ill patients into hospice care. One of the for-profit chain’s goals, according to the story, was to improve its mortality rates.
