Table 3 Baseline comorbidity characteristics of the aggregated cohort, comparing readmitted to non-readmitted patients in index stays for the Charlson and Elixhauser Indices

Charlson Index Composite

2.16 ± 1.43

2.10 ± 1.39

2.41 ± 1.57

<.001

 Index Score = 1

42.7%

44.2%

35.5%

<.001

 Index Score = 2

27.6%

27.5%

27.8%

 Index Score ≥ 3

29.7%

28.3%

36.8%

  Cerebrovascular disease

3.1%

3.0%

3.5%

<.001

  Dementia

1.8%

1.8%

1.9%

0.041

  Hemiplegia/paraplegia

0.3%

0.3%

0.3%

<.001

 Congestive heart failure

27.6%

26.1%

34.8%

<.001

 Peripheral vascular disease

5.6%

5.4%

6.2%

<.001

 Myocardial infarction

7.8%

7.6%

8.9%

<.001

 Chronic pulmonary disease

100.0%

100.0%

100.0%

–

 Peptic ulcer disease

0.8%

0.8%

0.9%

<.001

 Mild liver disease

2.2%

2.1%

2.4%

<.001

 Moderate or severe liver disease

0.2%

0.1%

0.2%

<.001

 Moderate or severe renal disease

14.0%

13.1%

18.1%

<.001

 HIV/AIDS

0.2%

0.2%

0.3%

<.001

 Malignancy (any type)

3.4%

3.2%

4.4%

<.001

 Metastatic solid tumor

1.1%

1.0%

1.7%

<.001

 Connective tissue disease

2.2%

2.2%

2.2%

0.131

 Diabetes mellitus

16.5%

16.4%

17.0%

<.001

 Diabetes mellitus w/end-organ damage

2.1%

2.0%

2.6%

<.001

Elixhauser Index Composite

17.0 ± 15.0

16.3 ± 14.7

20.5 ± 16.0

<.001

Elixhauser Comorbidity Domain Count

3.99 ± 1.84

3.92 ± 1.81

4.37 ± 1.91

<.001

 Paralysis

1.3%

1.2%

1.5%

<.001

 Other neurologic disorders

8.6%

8.3%

9.8%

<.001

 Alcohol abuse

4.5%

4.5%

4.7%

<.001

 Drug abuse

3.6%

3.5%

4.2%

<.001

 Psychoses

6.3%

6.1%

7.6%

<.001

 Depression

16.9%

16.7%

17.8%

<.001

 Congestive heart failure

26.9%

25.4%

34.0%

<.001

 Peripheral vascular disease

7.9%

7.7%

9.2%

<.001

 Valvular Heart Disease

6.5%

6.2%

7.5%

<.001

 Hypertension

54.1%

54.5%

52.2%

<.001

 Chronic pulmonary disease

100.0%

100.0%

100.0%

–

 Pulmonary circulation disorders

7.9%

7.6%

9.8%

<.001

 Peptic ulcer disease

0.1%

0.1%

0.2%

<.001

 Liver disease

2.4%

2.3%

2.8%

<.001

 Renal Failure

13.1%

12.3%

17.2%

<.001

 Fluid and electrolyte disorders

28.0%

27.4%

30.9%

<.001

 HIV/AIDS

0.2%

0.2%

0.3%

<.001

 Solid tumor without metastasis

3.4%

3.1%

4.6%

<.001

 Metastatic cancer

1.1%

1.0%

1.7%

<.001

 Lymphoma

0.5%

0.5%

0.6%

<.001

 Coagulopathy

3.2%

3.1%

3.8%

<.001

 Blood loss anemia

0.4%

0.3%

0.5%

<.001

 Deficiency anemia

15.4%

14.4%

19.9%

<.001

 Rheumatoid arthritis and collagen vascular disorders

3.3%

3.3%

3.5%

<.001

 Diabetes mellitus (uncomplicated)

26.3%

25.8%

28.4%

<.001

 Diabetes mellitus (complicated)

6.0%

5.7%

7.3%

<.001

 Hypothyroidism

13.7%

13.6%

14.0%

<.001

 Obesity

19.1%

19.0%

19.6%

<.001

 Weight loss

4.6%

4.5%

5.4%

<.001