To determine the cities where you don’t want to get sick, 24/7 Wall St. created an index using data for U.S. metropolitan statistical areas from the Centers for Medicare and Medicaid Services (CMS) and County Health Rankings. The index measures three sets of indicators: 30-day mortality rates, 30-day readmission rates, and preventable hospitalizations. Mortality and readmission rates each make up 42.1% of the index, and the rate of preventable hospitalizations makes up the remaining 15.8%.
The CMS produces statistics on numerous health measures for more than 4,000 Medicare-certified hospitals in the country. We grouped hospitals by metropolitan areas and aggregated the hospital data to the metropolitan statistical area level.
We calculated a weighted average of 30-day mortality rates for heart attacks, chronic obstructive pulmonary disease (COPD), coronary artery bypass grafting (CABG), heart failure, pneumonia, and stroke patients to find the average percentage of people who died within 30 days of being admitted to a hospital. The mortality measures are adjusted for differences in risk variables such as age, comorbidities — the presence of multiple ailments for a given patient — and patient frailty. CMS estimates the data for 30-day mortality by each condition per hospital from Medicare patients.
The readmission rate measures are estimates of unplanned readmission to an acute care hospital in the 30 days after discharge from a hospital for Medicare beneficiaries 65 or older. Patients may have an unplanned readmission for any reason.
Lastly, we used the share of hospitalizations for conditions that could have been treated at outpatient or ambulatory care facilities — often referred to as the preventable hospitalization rate. This measure counts hospitalizations for conditions such as asthma, dehydration, or hypertension per 1,000 Medicare enrollees. This data is from the 2019 County Health Rankings report, an annual analysis produced by the Robert Wood Johnson Foundation and University of Wisconsin Population Health Institute joint program.
Data on income are one-year estimates from the U.S. Census Bureau’s 2018 American Community Survey. Population figures are from the Census Bureau’s Population Projections program and are estimates for July 2018. Data on the share of residents living in urban and rural areas are from the Census Bureau’s 2010 decennial census.
Measures of individual health behaviors and outcomes including obesity, smoking rates, and sedentary lifestyles also came from County Health Rankings.