Table 1 Baseline characteristics of U.S. patients presenting to the ED, stratified by Emergency Severity Score, NHAMCS 2021

2211(25.4)

6505 (74.6)

Gender

0.0096

 Female

1149(52.0)

3587(55.1)

 Male

1062(48.0)

2918(44.9)

Age, y

 < 0.0001

 18–39

1071(48.4)

2264(34.8)

 40–65

792(35.8)

2455(37.7)

 >  = 65

348(15.7)

1786(27.5)

Race/ethnicity

0.0603

 White

1315(59.5)

3933(60.5)

 Black

537(24.3)

1496(23.0)

 Hispanic

293(13.3)

811(12.5)

 Other

66(3.0)

265(4.1)

Residence type

 < 0.0001

 Private residence

2067(95.8)

5944(94.2)

 Nursing home

22(1.0)

175(2.8)

 Homeless

48(2.2)

118(1.9)

 Other

21(1.0)

74(1.2)

Insurance type

 < 0.0001

 Private insurance

598(29.6)

1755(29.9)

 Medicare

385(19.0)

1748(29.7)

 Medicaid or CHIP

718(35.5)

1731(29.4)

 Uninsured

211(10.4)

468(8.0)

 Other

110(5.4)

177(3.0)

Day of Week

0.0085

 Weekdays

1600(72.4)

4891(75.2)

 Weekend

611(27.6)

1614(24.8)

Arrival time

0.0678

 Morning

660(30.1)

1857(28.7)

 Afternoon

646(29.5)

1987(30.7)

 Evening

382(17.4)

1016(15.7)

 Night

504(23.0)

1604(24.8)

Arrive by ambulance

179(8.2)

1615(25.4)

 < 0.0001

Follow-up visit

187(8.9)

444(7.4)

0.0243

Seen within last 72 h

78(3.7)

243(4.0)

0.5704

Pain level

0.2265

 No pain

644(37.1)

1933(39.4)

 Mild

569(32.8)

1556(31.7)

 Severe

524(30.2)

1416(28.9)

Temperature

0.0035

 36 °C–38 °C

2082(96.1)

5895(94.5)

 <  = 36 °C

59(2.7)

199(3.2)

 > 38 °C

26(1.2)

144(2.3)

Heart Rate, times/min

 < 0.0001

 61–90

1329(60.1)

3504(53.9)

 <  = 60

131(5.9)

422(6.5)

 > 90

751(34.0)

2579(39.6)

DBP mm Hg

0.0002

 60–80

978(44.2)

2762(42.5)

 < 60

125(5.7)

543(8.3)

 > 80

1108(50.1)

3200(49.2)

SBP mm Hg

0.1919

 80–120

486(22.0)

1438(22.1)

 < 80

31(1.4)

130(2.0)

 > 120

1694(76.6)

4937(75.9)

Pulse oximetry (percent)

 < 0.0001

 0–94

136(6.3)

731(11.5)

 95 + 

2037(93.7)

5648(88.5)

Respiratory rate per minute

 < 0.0001

 12–20

2066(93.4)

5651(86.9)

 < 12

48(2.2)

154(2.4)

 > 20

97(4.4)

700(10.8)

Injury/trauma, overdose/poisoning or adverse effect of medical/ surgical treatment

 < 0.0001

 Yes, injury/trauma

814(38.0)

1305(20.8)

 Yes, overdose/poisoning

24(1.1)

77(1.2)

 Yes, adverse effect of medical/surgical treatment

54(2.5)

200(3.2)

 No

1210(56.5)

4535(72.3)

 Questionable injury status

38(1.8)

155(2.5)

Medical History

 Alzheimer's disease/Dementia

18(0.8)

132(2.0)

0.0001

 Asthma

236(10.7)

761(11.7)

0.1909

 Cancer

55(2.5)

408(6.3)

 < 0.0001

 Cerebrovascular disease/History of stroke (CVA)

42(1.9)

343(5.3)

 < 0.0001

 Chronic kidney disease (CKD)

59(2.7)

382(5.9)

 < 0.0001

 Chronic obstructive pulmonary disease (COPD)

106(4.8)

538(8.3)

 < 0.0001

 Congestive heart failure (CHF)

60(2.7)

417(6.4)

 < 0.0001

 Coronary artery disease (CAD)

96(4.3)

670(10.3)

 < 0.0001

 Depression

298(13.5)

1027(15.8)

0.009

 Diabetes mellitus (DM)—Type I

13(0.6)

46(0.7)

0.5549

 Diabetes mellitus (DM)—Type II

139(6.3)

747(11.5)

 < 0.0001

 End-stage renal disease (ESRD)

12(0.5)

113(1.7)

 < 0.0001

 Pulmonary embolism (PE), deep vein thrombosis (DVT), or venous thromboembolism (VTE)

30(1.4)

162(2.5)

0.0017

 HIV infection/AIDS

16(0.7)

54(0.8)

0.628

 Hyperlipidemia

197(8.9)

1069(16.4)

 < 0.0001

 Hypertension

566(25.6)

2466(37.9)

 < 0.0001

 Obesity (BMI >  = 30)

164(7.4)

604(9.3)

0.0074

 Obstructive sleep apnea (OSA)

60(2.7)

249(3.8)

0.0144

 Osteoporosis

18(0.8)

108(1.7)

0.004

 Substance abuse or dependence

178(8.1)

665(10.2)

0.0028