Table 1 Sociodemographic and clinical characteristics of study participants according to biomarker patterns

Age (years), mean (SD)

75.3 (10.9)

75.7 (8.3)

79.8 (12.0)^b

66.9 (8.5)

< 0.001

Male sex, n (%)

49 (60.5)

17 (51.5)

19 (63.3)

13 (72.2)

0.325

Living alone, n (%)

35 (50.0)

14 (50.0)

15 (51.7)

6 (46.2)

0.946

Disability (any ADL or IADL lost), n (%)

36 (44.0)

13 (39.4)

19 (63.3)^b

4 (22.2)

0.016

Clinical Frailty Scale

4.2 (2.0)

3.7 (1.8)

5.3 (1.7)^{a, b}

3.2 (1.9)

< 0.001

Clinical Frailty Scale ≥ 5

34 (42.0)

11 (33.3)

19 (63.3)^{a, b}

4 (22.2)

0.010

Prescription drugs, n (%)

5.1 (3.6)

5.0 (4.0)

6.4 (3.3)^b

3.4 (2.6)

0.018

Time from symptoms onset and hospital admittance (days), mean (SD)

9.5 (8.2)

10.2 (9.8)

8.5 (7.4)

9.9 (6.4)

0.711

Hospital LOS (days), mean (SD)

24.7 (12.7)

24.4 (11.0)

28.3 (16.2)

20 (8.0)

0.450

In-hospital mortality, n (%)

15 (18.5)

6 (18.2)

7 (23.3)

2 (11.1)

0.621

Chronic conditions

Malnutrition, n (%)

21 (25.9)

5 (15.2)

13 (43.3)^a

3 (16.7)

0.029

Heart disease, n (%)

27 (33.3)

11 (33.3)

13 (43.3)

3 (16.7)

0.165

Stroke, n (%)

7 (8.6)

2 (6.1)

4 (13.3)

1 (5.6)

0.594

Dementia, n (%)

16 (19.8)

5 (15.2)

9 (30.0)

2 (11.1)

0.267

Chronic kidney disease, n (%)

9 (11.1)

0 (0.0)

9 (30.0)^{a, b}

0 (0.0)

< 0.001

Solid tumor, n (%)

9 (11.1)

6 (18.2)

1 (3.3)

2 (11.1)

0.165

COPD, n (%)

6 (7.4)

4 (12.1)

2 (6.7)

0 (0.0)

0.364

Characteristics at hospital admission

Respiratory rate ≥ 20/min, n (%)

32 (39.5)

18 (54.5)

11 (36.7)

3 (16.7)

0.028

Heart rate ≥ 100/min, n (%)

18 (22.2)

9 (27.3)

4 (13.3)

5 (27.8)

0.336

Fever, n (%)

25 (30.9)

12 (36.4)

7 (23.3)

6 (33.3)

0.518

Positive chest x-ray, n (%)

69 (85.2)

31 (93.9)

23 (76.7)

15 (83.3)

0.151

Brescia COVID scale

0.022

Ambient air, n (%)

14 (17.3)

6 (18.2)

7 (23.3)^{a, b}

1 (5.6)

Oxygen support, n (%)

31 (38.3)

9 (27.3)

13 (43.3)^a

9 (50.0)

Oxygen support, distressed patient, n (%)

24 (29.6)

11 (33.3)

10 (33.3)

3 (16.7)

Continuous Positive Air Pressure ventilation, n (%)

12 (14.8)

7 (21.2)

0 (0.0)^{a, b}

5 (27.8)

White blood cells (10³/mL), mean (SD)

7.3 (3.2)

7.3 (3.0)

7.4 (3.3)

7.0 (3.3)

0.918

C-reactive protein (mg/mL), mean (SD)

8.3 (6.8)

8.2 (5.7)

7.5 (7.9)

9.7 (6.9)

0.595

Lymphocytes (10³/mL, mean (SD)

1.2 (0.5)

1.1 (0.5)

1.3 (0.6)

1.2 (0.6)

0.625

Creatinine (mg/mL), mean (SD)

1.4 (1.5)

1.0 (0.3)

2.1 (2.3)^{a, b}

0.9 (0.2)

0.004