Skip to main content

Table 1 Patient characteristics and in-hospital mortality overall and by hospital case volume level for discharges with a principal diagnosis of pneumonia, Japanese DPC database, 2010

From: Association between hospital case volume and mortality in non-elderly pneumonia patients stratified by severity: a retrospective cohort study

 

Total

Very low (≤7)

Low (8–11)

Medium (12–17)

High (≥18)

p†

Number of patients

8293

1771

2020

2146

2356

 

Sex (male, %)

57.6%

59.7%

59.3%

55.5%

56.4%

0.01

Age

     

0.11

 18–44 years

37.9%

36.8%

36.5%

40.5%

37.4%

 

 45–54 years

15.7%

15.3%

15.6%

15.5%

16.3%

 

 55–64 years

46.4%

47.9%

47.8%

44.0%

46.3%

 

Charlson comorbidity index

     

0.16

 0

43.9%

44.0%

42.2%

43.1%

46.1%

 

 1 or 2

42.8%

42.3%

43.3%

43.2%

42.2%

 

 3–6

11.1%

11.2%

12.0%

11.4%

10.0%

 

 7 and above

2.2%

2.6%

2.4%

2.2%

1.7%

 

Referred from clinics/other hospitals

36.9%

36.0%

35.6%

42.4%

33.5%

<.001

Severity Indices

      

 BUN ≥21 mg/dL or signs of dehydration

19.8%

22.7%

19.7%

19.3%

18.4%

0.01

 SpO2 ≤ 90% (or ≤ PaO2 60 Torr)

22.1%

21.0%

22.7%

21.9%

22.5%

0.60

 Presence of cognitive disturbance

8.0%

8.0%

8.0%

8.4%

7.6%

0.79

 Systolic blood pressure ≤90 mmHg

7.6%

9.3%

8.2%

7.1%

6.4%

0.004

Academic hospital

12.1%

11.5%

14.9%

11.1%

10.9%

<.001

In-hospital death

3.3%

3.8%

3.6%

3.4%

2.6%

0.14

  1. †p-value from chi-squared test for independence.
  2. BUN: blood urea nitrogen; SpO2: oxygen saturation; PaO2: arterial oxygen tension.