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Table 1 Patient Demographics and Characteristics

From: Assessing stroke severity using electronic health record data: a machine learning approach

Characteristic

Training set (n = 6116)

Hold-out test set (n = 1033)

Overall population (n = 7149)

Demographics

 Age, mean (SD)

66 (14)

67 (14)

66 (14)

 Female, n (%)

3196 (52)

568 (55)

3764 (53)

 Region

  Northeast, n (%)

464 (8)

84 (8)

548 (8)

  Midwest, n (%)

2388 (39)

389 (38)

2777 (39)

  South, n (%)

2957 (48)

496 (48)

3453 (48)

  West, n (%)

186 (3)

40 (4)

226 (3)

  Other/Unknown, n (%)

121 (2)

24 (2)

145 (2)

EHR data

 NIHSS, median (IQR)

2 (6)

2 (6)

2 (6)

 LOS, median (IQR)

3 (5)

2 (4)

3 (5)

 Type of strokea

  Ischemic, n (%)

4328 (70.8)

710 (68.7)

5038 (70.5)

  Hemorrhagic, n (%)

605 (10.0)

113 (10.9)

718 (10.0)

  TIA, n (%)

2235 (36.5)

384 (37.2)

2619 (36.6)

Charlson Comorbidity Indexb, median (IQR)

1 (3)

1 (3)

1 (3)

  1. SD standard deviation, EHR Electronic Health Record, NIHSS National Institutes of Health Stroke Scale, IQR interquartile range, LOS length of stay, TIA transient ischemic attack
  2. aBased on ICD diagnosis codes during stroke event; more than one type may be coded per patient stroke event
  3. bCalculated based on patients’ diagnosis codes prior to stroke [15]