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Table 2 Patient Cohort Demographics

From: A machine learning model to predict the risk of 30-day readmissions in patients with heart failure: a retrospective analysis of electronic medical records data

Patient Characteristics Whole Cohort Patients with readmissions Patients without readmissions p-value
N = 11,510 n = 3502 n = 8008
Age Distribution     0.75
 Median (1, 3 quartile) 75.7 (64.3, 84.7) 76.0 (64.4, 84.6) 75.5 (64.2, 84.7)  
Gender, n (%)     0.74
 Male 6073 (52.8) 1839 (52.5) 4234 (52.9)  
Race, n (%)     0.16
 White 9490 (84.5) 2872 (83.8) 6618 (84.9)  
 Black or African American 889 (7.9) 297 (8.7) 592 (7.6)  
 Hispanic or Latino (all races) 423 (3.8) 141 (4.1) 282 (3.6)  
 Asian 221 (2.0) 61 (1.8) 160 (2.1)  
 Other, or more than one race 202 (1.8) 58 (1.7) 144 (1.8)  
Unknown (excluded in calculations) n = 285 n = 73 n = 212  
Marital status, n (%)     0.07
 Married / Partnered 5125 (45.6) 1516 (44.3) 3609 (46.2)  
 Widow 2360 (21.0) 718 (21) 1642 (21)  
 Single 2274 (20.2) 715 (20.9) 1559 (19.9)  
 Divorced / Separated 1069 (9.5) 323 (9.4) 746 (9.5)  
 Other 412 (3.7) 148 (4.3) 264 (3.4)  
Unknown (excluded in calculations) n = 270 n = 82 n = 188  
Highest educational attainment, n (%)     < 0.01*
 Some High School or Less 1117 (12.7) 392 (14.2) 725 (12)  
 High School Graduate/GED 3418 (38.7) 1127 (40.7) 2291 (37.8)  
 Some College/Vocational/Technical Program 492 (5.6) 134 (4.8) 358 (5.9)  
 Graduate of College or Postgraduate School 2911 (33.0) 864 (31.2) 2047 (33.8)  
 Other 887 (10.1) 253 (9.1) 634 (10.5)  
Unknown (excluded in calculations) n = 2685 n = 732 n = 1953  
Employment status, n (%)     < 0.01*
 Retired 4338 (57.3) 1329 (57.7) 3009 (57.1)  
 Employed a 2067 (27.3) 556 (24.1) 1511 (28.7)  
 Disability 656 (8.7) 259 (11.2) 397 (7.5)  
 Unemployed 467 (6.2) 149 (6.5) 318 (6)  
 Other 49 (0.6) 12 (0.5) 37 (0.7)  
Unknown (excluded in calculations) n = 3933 n = 1197 n = 2736  
Number of comorbidities, n (%) b     < 0.01*
 0 2619 (22.8) 578 (16.5) 2041 (25.5)  
 1 3032 (26.3) 840 (24) 2192 (27.4)  
 2 2684 (23.3) 841 (24) 1843 (23)  
  ≥ 3 3175 (27.6) 1243 (35.5) 1932 (24.1)  
  1. aIncludes part-time and self-employment
  2. bThe following list of comorbidities was selected based on a literature review of comorbidities frequently found in patients with heart failure [27,28,29,30,31,32,33], in addition to clinical opinion of study staff physicians. Please see Additional file 3: Appendix B for a complete list of ICD-9 codes used to identify each condition. Each condition evaluated is listed here with the percentage of the study population who presented to a PHS facility with the condition as the principal diagnosis for either an inpatient or outpatient encounter at least once between 2014 and 2015. Hypertension (37.3%), cardiovascular disease (32.5%), chronic kidney disease / renal insufficiency (26.1%), non-secondary diabetes mellitus (22.8%), anemia (19.2%), chronic obstructive pulmonary disease (9.8%), osteoarthritis (9.1%), mental health conditions (7.2%), back pain (3.3%), osteoporosis (3.2%), obesity (2.3%)