NATIONAL HEALTH INDEX

Methodology

The Healthgrades National Health Index reflects health and healthcare in 100 metropolitan areas based on data from four primary sources: the Centers for Disease Control and Prevention (CDC), healthgrades.com survey scores and provider information, the United States Census Bureau, and Healthgrades’ 2019 award year hospital quality ratings.4
UNDERSTANDING THE RANKINGS
Sophisticated algorithms uncovered patterns in this data, revealing the four key factors — or combinations of variables — that informed the final ranking.
ACCESS TO CARE
ACCESS TO CARE
The percentage of the population reporting: 1) they have any kind of healthcare coverage, 2) that cost did not restrict seeing a doctor when needed, 3) they think of at least one person as their personal doctor or healthcare provider, and 4) for residents ages 50 to 75, that they had a colonoscopy in the past 10 years.
POPULATION HEALTH
POPULATION HEALTH
The percentage of the population: 1) in good or better health, 2) with a normal Body Mass Index (BMI), 3) who report participating in any physical activities during the past month, and 4) who visited a dentist within the past year.
HOSPITAL QUALITY
HOSPITAL QUALITY
1) The percentage of all hospital quality ratings awarded in the market that were 5-star, 2) the percentage of hospitals in the market that have demonstrated clinical excellence across multiple conditions and procedures, and 3) the market’s average statistical measure of hospital clinical outcomes.
LOCAL SPECIALISTS
LOCAL SPECIALISTS
The number of: 1) select specialists per capita, 2) select specialists per capita with an average Healthgrades Patient Experience Survey score ≥4.5, and 3) select specialists per capita with an average Healthgrades Patient Experience Survey score of 5.
DATA SOURCES

To create the index, 130 metropolitan areas were examined in data from four sources:

  1. 01
    Selected responses from the Centers for Disease Control and Prevention (CDC) Behavioral Risk Factor Surveillance System (BRFSS) 2016 survey at the Metropolitan Statistical Area (MSA) level 1
  2. 02
    Provider specialty information and patient experience survey scores available from Healthgrades.com at the Core Based Statistical Area (CBSA) accessed on September 5, 2018 2
  3. 03
    2017 population estimates from the United States Census Bureau 3
  4. 04
    Healthgrades 2019 award year hospital quality ratings at the MSA level 4
Healthgrades 2019 National Health Index Methodology

In cases where BRFSS data divided MSAs into Metropolitan Divisions, responses taken from the primary city in the MSA were used. Hospital quality variables were also calculated at the Metropolitan Division, while provider specialty data were examined at the larger Metropolitan Statistical Area.

Data analysis was performed using the R statistical programming language. To explore the latent structure of the data, a principal component analysis (PCA) was performed on scaled data. Examination of a scree plot and component eigenvalues indicated that a four-component model best explained the underlying low dimensional structure of the data.

Consequently, a maximum-likelihood factor analysis fitted to four factors was produced on the data matrix using a varimax rotation. This model explained 51.2% of the cumulative variance. A chi-square test, evaluating the explanatory sufficiency of a four factor model, was statistically significant (χ2 = 328.59, df = 116, p < .0001).

To optimize the interpretability of the factor model, only each variable’s greatest positive factor weight above 0.4 was used to create the final factor scores. As a result, the following six variables were not retained in any final factor score.

  • Percentage of population reporting having visited a doctor in the last year for routine check-up
  • Percentage of population that have never been told they have a form of depression
  • Percentage of women aged 40+ who have had a mammogram within the past two years
  • Number of providers who treat a high or very high patient volume for select diseases, conditions, or procedures
  • Percentage of hospitals receiving the Healthgrades 2018 Outstanding Patient Experience Award
  • Percentage of hospitals receiving the Healthgrades 2018 Patient Safety Excellence Award.

The Factor Loading Table displays the factor loadings for each variable input into the analysis used to construct the National Health Index.

For each factor, a variable’s population value was multiplied against the factor weight and added to the product of all variables in a factor, creating a final factor score. Next, the four factor scores were cumulatively added to obtain the total factor score for each metropolitan area. Each metropolitan area was then ranked from highest to lowest total factor score to determine the final list of 100 cities for the National Health Index.

Table 1. Factor Loading Table.
FACTOR 1
Access to Care
FACTOR 2
Population Health
FACTOR 3
Hospital Quality
FACTOR 4
Local Specialists
Percentage of population in good or better health status
0.243
0.816
0.122
0.041
Percentage of population with a normal Body Mass Index (BMI)
0.512
0.147
0.186
Percentage of population reporting having visited a doctor in the last year for routine check-up~
0.359
-0.514
0.138
Percentage of population reporting having any kind of healthcare coverage
0.879
0.142
0.182
Percentage of population reporting participation in any physical activities during the past month
0.207
0.811
0.207
Percentage of population reporting that cost did not restrict seeing a doctor when needed
0.755
0.395
Percentage of population that have never been told they have a form of depression~
-0.307
0.181
0.101
Percentage of population that visited a dentist or dental clinic within the past year for any reason
0.567
0.591
0.129
0.103
Percentage of women ages 40 or older who have had a mammogram within the past two years~
0.360
-0.108
0.131
Percentage of people ages 50 to 75 who had a colonoscopy in the past 10 years
0.552
0.168
Percentage of population reporting that they think of at least one person as their personal doctor or healthcare provider
0.817
Percentage of all hospital ratings in the market that were awarded 5 stars
0.106
0.830
0.123
Number of providers who treat a high or very high patient volume for select diseases, conditions or procedures#~
0.170
-0.534
0.248
Number of select specialists* per capita
0.277
0.231
0.786
Number of select specialists* per capita with Healthgrades patient experience surveys scoring an average of >= 4.5†
-0.198
0.600
Number of select specialists* per capita with Healthgrades patient experience surveys scoring an average of 5†
0.151
0.205
0.856
Percentage of hospitals in the market that have demonstrated clinical excellence across multiple conditions and procedures
0.170
0.669
Percentage of hospitals receiving the Healthgrades 2018 Outstanding Patient Experience Award~
-0.157
0.209
0.211
0.168
Percentage of hospitals receiving the Healthgrades 2018 Patient Safety Excellence Award~
-0.234
-0.177
0.174
Average Healthgrades hospital quality total volume-weighted z-score
0.241
0.763
~ Variables not retained in any final factor score
* Specialists Examined: Cardiologists, Orthopedic Surgeons, Obstetrician-Gynecologists, Endocrinologists, Psychiatrists, Neurosurgeons, and Rheumatologists
# Diseases, conditions, and procedure information from the following: diabetes, breast cancer, valve replacements, hip or knee replacement, COPD, and rheumatoid arthritis
† Minimum of 10 patient experience surveys in calculation
1   Centers for Disease Control and Prevention (CDC). Behavioral Risk Factor Surveillance System Survey Data. Atlanta, Georgia: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, 2016.
2   Provider specialty information and patient experience survey scores available from Healthgrades.com at the Core Based Statistical Area (CBSA) accessed on September 5, 2018.
3   U.S. Census Bureau. Annual Estimates of the Resident Population: April 1, 2010 to July 1, 2017. Release Date: March 2018. https://factfinder.census.gov/faces/nav/jsf/pages/index.xhtml, 2017.
4  Healthgrades Mortality and Complications Outcomes 2019 Methodology. Available at: https://www.healthgrades.com/quality/2019-methodology-mortality-and-complications-outcomes.

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