Table 3 Multivariable model

 Certain early complications of trauma (T79)

–

2.221 (1.998, 2.468)

< 0.001

 Burns and corrosions (T20-T32)

–

1.550 (1.454, 1.651)

< 0.001

 Other and unspecified effects of external causes (T66-T78)

–

1.547 (1.484, 1.613)

< 0.001

 Poisoning by, adverse effect of, and underdosing of drugs, medicaments, and biological substances (T36-T50)

–

1.350 (1.287, 1.416)

< 0.001

 Injuries to the head (S00-S09)

–

1.286 (1.258, 1.316)

< 0.001

 Toxic effects of substances chiefly nonmedicinal as to source (T51-T65)

–

1.274 (1.191, 1.362)

< 0.001

 Injuries to the elbow and forearm (S50-S59)

–

1.203 (1.163, 1.245)

< 0.001

 Injuries to the wrist, hand, and fingers (S60-S69)

–

1.180 (1.151, 1.209)

< 0.001

 Injuries to the hip and thigh (S70-S79)

–

1.139 (1.098, 1.182)

< 0.001

 Injuries involving multiple body regions (T07)

–

1.071 (1.022, 1.123)

0.004

 Injury of unspecified body region (T14-T14)

–

1.062 (1.023, 1.104)

0.002

 Injuries to the abdomen, lower back, lumbar spine, pelvis, and external genitals (S30-S39)

–

1.038 (1.010, 1.068)

0.008

 Injuries to the knee and lower leg (S80-S89)

–

1.035 (1.006, 1.066)

0.018

 Injuries to the shoulder and upper arm (S40-S49)

–

0.951 (0.921, 0.981)

0.002

 Injuries to the ankle and foot (S90-S99)

–

0.947 (0.919, 0.975)

< 0.001

 Injuries to the thorax (S20-S29)

–

0.923 (0.895, 0.951)

< 0.001

 Effects of foreign body entering through natural orifice (T15-T19)

–

0.866 (0.800, 0.938)

< 0.001

 Length of stay, hours

[0, 1)

Ref

< 0.001

[1, 12)

1.352 (1.308, 1.398)

12 or more

1.742 (1.638, 1.852)

 Payer

Commercial

Ref

< 0.001

Medicare/Medicaid

1.283 (1.252, 1.314)

Other governmental

1.188 (1.131, 1.247)

Self-pay

1.225 (1.191, 1.259)

Others

1.176 (1.137, 1.216)

 Age (years)

[0, 50)

Ref

[50 70)

1.025 (1.003, 1.047)

0.024

[70 or older)

1.125 (1.092, 1.159)

< 0.001

 Race/ethnicity

Caucasian

Ref

Hispanic

0.873 (0.815, 0.935)

< 0.001

African American/Black

0.946 (0.922, 0.971)

< 0.001

Asian/Pacific Islander

0.916 (0.836, 1.004)

0.062

Native American

1.036 (0.974, 1.101)

0.262

Others/Unknown

0.902 (0.870, 0.935)

< 0.001

 Sex

Female

Ref

Male

1.198 (1.177, 1.219)

< 0.001

Others/known

0.888 (0.606, 1.300)

0.541

 Previous hospitalization (prior 6 months)

0

Ref

< 0.001

1

1.263 (1.223, 1.305)

2

1.369 (1.295, 1.448)

3 or more

1.61 (1.512, 1.715)

 Index ED visit is itself a return visit

Yes

1.505 (1.46, 1.551)

< 0.001

 Number of previous ED visits (prior 6 months)

0

Ref

< 0.001

1

1.301 (1.27, 1.333)

2

1.655 (1.603, 1.708)

3 or more

2.145 (2.078, 2.214)

 Number of previous return visits (prior 6 months)

0

Ref

< 0.001

1

1.38 (1.326, 1.436)

2

2.012 (1.897, 2.135)

3 or more

4.014 (3.825, 4.213)

 Diseases of the circulatory system (I00-I99)

–

1.032 (1.005, 1.060)

0.020

 Disease of the nervous system (G00-G99)

–

1.085 (1.052, 1.118)

< 0.001

 Complications of surgical and medical care, not elsewhere classified (T80-T88)

–

1.364 (1.301, 1.43)

< 0.001