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. Author manuscript; available in PMC: 2019 Jun 1.
Published in final edited form as: Acad Emerg Med. 2017 Dec 11;25(6):657–667. doi: 10.1111/acem.13342

Table 4. Multivariable logistic regression models predicting high-frequency emergency department utilization for asthma among adult patients for State-wide and Single-center Visits (n=159,874).

State-wide Visits
(index and non-index hospitals)
Single-center Visits
(index hospitals only)
Derivation set Test set Derivation set Test set
OR (95%CI) p-value OR (95%CI) p-value OR (95%CI) p-value OR (95%CI) p- value
Age at index visit in years 0.99 (0.992-0.997) <0.001 0.99 (0.991-0.996) <0.001 - -
Female 0.81 (0.76-0.87) <0.001 0.78 (0.73-0.84) <0.001 0.85 (0.78-0.93) <0.001 0.81 (0.74-0.88) <0.001
Race/ethnicity
White Reference Reference
Black - - 1.24 (1.12-1.38) <0.001 1.20 (1.08-1.34) 0.001
Hispanic - - 1.04 (0.92-1.17) 0.54 1.15 (1.02-1.29) 0.02
Other - - 0.88 (0.75-1.02) 0.09 0.81 (0.69-0.95) 0.01
Median household income by patient ZIP code
<$39,000 Reference Reference Reference Reference
$39,000 - $47,999 0.69 (0.63-0.76) <0.001 0.68 (0.62-0.74) <0.001 0.73 (0.65-0.82) <0.001 0.69 (0.61-0.77) <0.001
$48,000 - $62,999 0.68 (0.62-0.75) <0.001 0.70 (0.64-0.78) <0.001 0.69 (0.61-0.77) <0.001 0.69 (0.61-0.78) <0.001
$63,000 and over 0.63 (0.57-0.70) <0.001 0.69 (0.62-0.76) <0.001 0.56 (0.49-0.64) <0.001 0.62 (0.54-0.70) <0.001
Primary expected payer
Medicare Reference Reference Reference Reference
Medicaid 1.20 (1.07-1.33) 0.001 1.24 (1.11-1.39) <0.001 1.17 (1.04-1.32) 0.01 1.22 (1.09-1.38) 0.001
Private Insurance 0.61 (0.54-0.70) <0.001 0.60 (0.53-0.68) <0.001 0.62 (0.54-0.72) <0.001 0.65 (0.56-0.76) <0.001
Self-pay 0.99 (0.87-1.13) 0.9 1.06 (0.93-1.22) 0.38 1.00 (0.86-1.15) 0.95 1.08 (0.93-1.26) 0.31
No charge/other 0.87 (0.71-1.08) 0.21 1.01 (0.81-1.24) 0.95 0.94 (0.73-1.20) 0.29 0.96 (0.74-1.24) 0.76
Prior state-wide ED visits for any cause (≥ 4 ED visits) 5.79 (5.39-6.21) <0.001 5.98 (5.57-6.42) <0.001 5.31 (4.88-5.78) <0.001 5.45 (5.00-5.94) <0.001
Index visit months by quarter
January - March Reference Reference Reference Reference
April - June 0.61 (0.56-0.67) <0.001 0.60 (0.55-0.65) <0.001 0.58 (0.53-0.65) <0.001 0.54 (0.49-0.60) <0.001
July - September 0.48 (0.43-0.52) <0.001 0.47 (0.42-0.52) <0.001 0.44 (0.39-0.50) <0.001 0.42 (0.37-0.48) <0.001
October - December 0.40 (0.36-0.45) <0.001 0.43 (0.38-0.47) <0.001 0.37 (0.32-0.42) <0.001 0.39 (0.34-0.45) <0.001
Index visit time of presentation
1 am - 6 am Reference Reference
7 am - 12 pm - - 0.90 (0.79-1.04) 0.15 0.89 (0.77-1.02) 0.09
1 pm - 6 pm - - 0.85 (0.74-0.98) 0.02 0.84 (0.73-0.96) 0.01
7 pm - 12 am - - 0.95 (0.82-1.09) 0.46 0.89 (0.77-1.02) 0.10
Day of index visit
Monday - Friday Reference Reference
Saturday - Sunday 1.05 (0.97-1.13) 0.25 1.07 (0.99-1.15) 0.09 - -

Abbreviations: OR, odds ratio; 95%CI, 95% confidence interval; ED, emergency department