Table 1 Characteristics of eligible patients categorised by the occurrence of in-hospital death

Age (years)

83.1 (8.7)

82.9 (8.7)

85.7 (7.6)

 < 0.001

Male

1,732 (43.8%)

1,575 (43.7%)

157 (44.9%)

0.68

BMI (kg/m²)

21.3 (4.0)

21.5 (4.0)

19.8 (4.0)

 < 0.001

BMI category

Low, ≤ 18.5 kg/m²

987 (25.0%)

841 (23.3%)

146 (41.7%)

 < 0.001

Medium–low, 18.6–21.0 kg/m²

989 (25.0%)

912 (25.3%)

77 (22.0%)

Medium–high, 21.1–23.7 kg/m²

986 (24.9%)

918 (25.5%)

68 (19.4%)

High, ≥ 23.8 kg/m²

990 (25.1%)

931 (25.8%)

59 (16.9%)

BMI category in Japan

Lean, < 18.5 kg/m²

969 (24.5%)

825 (22.9%)

144 (41.1%)

 < 0.001

Normal, 18.5–24.9 kg/m²

2,329 (58.9%)

2,158 (59.9%)

171 (48.9%)

Obese, ≥ 25.0 kg/m²

654 (16.5%)

619 (17.2%)

35 (10.0%)

Smoking history

Non-smoker

2,440 (61.7%)

2,205 (61.2%)

235 (67.1%)

0.029

Current/past smoker

1,512 (38.3%)

1,397 (38.8%)

115 (32.9%)

Estimated glomerular filtration rate (ml/min/1.73 m²)

40.6 (13.6)

41.0 (13.3)

36.6 (15.7)

 < 0.001

CKD staging

CKD stage G3

3,054 (77.3%)

2,829 (78.5%)

225 (64.3%)

 < 0.001

CKD stage G4

674 (17.1%)

589 (16.4%)

85 (24.3%)

CKD stage G5

224 (5.7%)

184 (5.1%)

40 (11.4%)

Creatinine clearance (ml/min)

31.8 (14.3)

32.5 (14.3)

25.0 (12.2)

 < 0.001

Dehydration

2,414 (61.1%)

2,129 (59.1%)

285 (81.4%)

 < 0.001

Respiratory failure

None

2,129 (53.9%)

2,030 (56.4%)

99 (28.3%)

 < 0.001

Moderate

1,301 (32.9%)

1,181 (32.8%)

120 (34.3%)

Severe

522 (13.2%)

391 (10.9%)

131 (37.4%)

Orientation disturbance

648 (16.4%)

495 (13.7%)

153 (43.7%)

 < 0.001

Immunosuppression

664 (16.8%)

588 (16.3%)

76 (21.7%)

0.010

Pulmonary consolidation

1,033 (26.1%)

882 (24.5%)

151 (43.1%)

 < 0.001

Hypotension on admission

288 (7.3%)

223 (6.2%)

65 (18.6%)

 < 0.001

Pneumonia type

Community-acquired

3,724 (94.2%)

3,412 (94.7%)

312 (89.1%)

 < 0.001

Nursing and healthcare-associated

228 (5.8%)

190 (5.3%)

38 (10.9%)

Charlson comorbidity index

1.7 (1.7)

1.6 (1.6)

2.0 (1.9)

 < 0.001