Appendix Table 1: Description of Variables Chosen for Inclusion in Multivariable Model

Appendix Table 1: Description of Variables Chosen For Inclusion In Multivariable Model

Characteristic / Definition(10)
Age / Patient age at time of ED evaluation (years) calculated from the birth date to the admission date
Female / Female Sex
Primary Payer / Expected primary payer including: Medicare, Medicaid, Private Insurance, Self-pay, No charge, and Other
Low-income / Individual whose national quartile for the median household income of the documented patient zips code was in the lowest category. The cut-offs for the categories changed across the years as follows: 2007: $1 - $38999; 2008 and 2009: $1 - $39999.
Weekend ED visit / ED visit occurred on Saturday or Sunday
Chronic Condition Indicator / NEDS contains a chronic condition indicator that categorizes ICD-9 diagnoses into chronic or not chronic. We chose to review ICD-9 codes listed in the 2nd through 5th ED diagnosis fields (all included patients had AF listed as their primary diagnosis) for the following diseases that are associated with increased cardiovascular morbidity and mortality for our model. The disease must be listed as chronic to be entered into the multivariable analysis
Diabetes / ICD-9 codes 250.00, 250.01, 250.02, 250.03
Coronary artery disease / ICD-9 codes 412, 414.00, 414.01, 414.02, 414.03, 414.04, 414.05, 414.06, 414.07, 414.8, 414.9
Chronic obstructive pulmonary disease / ICD-9 codes 491, 492, 496
Heart failure / ICD-9 code 428
Large metropolitan status / EDs were classified as large metropolitan if their value for hospital category was “large metropolitan areas” with at least 1 million residents. Those that were classified as not being in a large metropolitan area had hospital category values including: 1) small metropolitan areas with less than 1 million residents; 2) micropolitan areas; 3) not metropolitan or micropolitan; 4) non-metropolitan collapsed category of micropolitan and rural.
Teaching hospital / NEDS contains a teaching status variable for the participating hospital. The hospital's teaching status was obtained from the AHA Annual Survey of Hospitals. A hospital is considered to be a teaching hospital if it has an AMA-approved residency program, is a member of the Council of Teaching Hospitals (COTH) or has a ratio of full-time equivalent interns and residents to beds of .25 or higher.(10)
Safety net hospital / Safety net hospital status defined as meeting at least one of the following criteria: Meets either one of these criteria: 1) > 30% Medicaid visits or > 30% self pay or no charge visits; 2) > 40% combined Medicaid and self pay or no charge visits(23)
Hospital Control (Ownership) / Control/ownership of hospital is defined in NEDS as the following categories: government or private, collapsed category; government, nonfederal, public; private, non-profit, voluntary; private, invest-own; private, collapsed category