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Table 1 Characteristics of patients in the derivation and validation cohorts

From: Electronic medical record-based multicondition models to predict the risk of 30 day readmission or death among adult medicine patients: validation and comparison to existing models

Characteristica Derivation (n = 19 831) Validation (n = 19 773)
Age, y (mean) 61.3 (17.7) 61.1 (17.5)
Male 9 207 (46.4) 9 182 (46.4)
Race White 12 361 (62.3) 12 344 (62.4)
  Black 3 911 (19.7) 3 985 (20.2)
  Hispanic 2 762 (13.9) 2 670 (13.5)
Payor, Medicare 8 191 (41.3) 8 005 (40.5)
  Medicaid 1 371 (6.9) 1 414 (7.1)
  Commercial 7 556 (38.1) 7 473 (37.8)
  Self-Pay 944 (4.8) 1 019 (5.2)
Elective admission 2 823 (14.2) 2 770 (14.0)
At least 1 prior hospitalization in past year 4 495 (22.7) 4 489 (22.7)
At least 1 prior ED visit in past year 5 653 (28.5) 5 715 (28.9)
Number of emergency contacts in EMR (up to 5)   
 0 643 (3.2) 654 (3.3)
 1 16 107 (81.2) 16 000 (80.9)
 2 2 846 (14.4) 2 865 (14.5)
 3 – 5 235 (1.2) 254 (1.3)
Principal diagnosis disease category   
 Cardiorespiratory condition 2 631 (13.3) 2 482 (12.6)
 Cardiovascular condition 2 425 (12.2) 2 549 (12.9)
 Neurologic condition 1 104 (5.6) 1 098 (5.5)
Comorbidities (available within 24 h of admission)b   
 Coronary atherosclerosis or angina, cerebrovascular disease 2 423 (12.2) 2 518 (12.7)
 Diabetes mellitus 2 254 (11.4) 2 317 (11.7)
 Congestive heart failure 1 504 (7.6) 1 474 (7.5)
 Iron deficiency 1 344 (6.8) 1 380 (7.0)
 Acute renal failure 1 261 (6.4) 1 237 (6.3)
 Disorders of fluid, electrolyte, acid-base 1 214 (6.1) 1 241 (6.3)
 Arrhythmias 1 205 (6.1) 1 204 (6.1)
 Psychiatric disease 979 (4.9) 990 (5.0)
 Chronic obstructive pulmonary disease 766 (3.9) 782 (4.0)
 Pneumonia and other infectious diseases 737 (3.7) 745 (3.8)
Laboratory results/vitals within 24 h of admission, median (IQR)   
 Albumin 3.5 (3.1 – 3.9) 3.6 (3.1 – 3.9)
 Creatinine 1 (0.8 – 1.4) 1 (0.8 – 1.4)
 Hematocrit 37.7 (33.4 – 41.3) 37.6 (33.3 – 41.2)
 Potassium 4.1 (3.8 – 4.5) 4.1 (3.8 – 4.5)
 Respiratory rate 20 (20 – 24) 20 (20 – 24)
 Systolic blood pressure 155 (139 – 176) 154 (139 – 176)
 Reported pain level on scale of 0 – 10 0 (0 – 4) 0 (0 – 4)
Outcomes   
 30-day mortality 621 (3.1) 548 (2.8)
 30-day readmission 2 638 (13.3) 2 504 (12.7)
 30 day readmission or mortality 3 116 (15.7) 2 906 (14.7)
 Length of stay, median (IQR) 4 (2 – 7) 4 (2 – 6)
  1. Abbreviations: EMR, electronic medical record; IQR, interquartile range. aNumbers (percent) unless otherwise stated bComorbidities for admissions in the prior year, not index admission, coded using ICD-9 diagnoses