Table 2– Clinical characteristics at admission

	Non-purulent	Purulent	p-value
Subjects n	34	39
Temperature ≥38°C	9 (26)	12 (32)	0.52
Respiratory rate breaths·min⁻¹	25 (23–32)	25 (24–32)	0.93
Heart rate beats·min⁻¹	98 (90–113)	97 (88–110)	0.78
Type of exacerbation (Anthonisen criteria)
Type I	0	32 (82)	<0.0001
Type II	18 (53)	7 (18)	0.076
Type III	16 (47)	0	0.001
Leukocyte count ×10⁹ cells·L⁻¹	8.82 (7–11)	10.54 (8.4–12.7)	0.19
CRP on admission mg·dL⁻¹	5.3 (0.10–23.0)	11.6 (0.10–33.0)	0.006
CRP on day 3 mg·dL⁻¹	1.2 (0.10–15.6)	2.7 (0.10–18.1)	0.01
PCT on admission ng·mL⁻¹	0.04 (0.01–0.10)	0.05 (0.02–0.13)	0.89
PCT <0.1 ng·mL⁻¹	24 (46)	28 (54)
PCT 0.1–0.25 ng·mL⁻¹	4 (36)	7 (63)
PCT >0.25 ng·mL⁻¹	4 (40)	6 (60)
PCT on day 3 ng·mL⁻¹	0.03 (0.01–0.05)	0.04 (0.02–0.07)	0.32
CRP on admission mg·dL⁻¹
Type I		12.4 (0.80–26.2)
Type II	5.8 (0.10–22.1)	8.7 (1.2–17.3)	0.20
Type III	2.9 (0.20–9.5)
PCT on admission ng·mL⁻¹
Type I		0.08 (0.02–0.20)
Type II	0.03 (0.01–0.10)	0.04 (0.02–0.10)	0.49
Type III	0.02 (0.01–0.10)
pH	7.39±0.06	7.41±0.05	0.15
P_a,CO₂ mmHg	45.1±12.3	39.5±6.4	0.14
P_a,O₂ mmHg	53.3±4.6	57.9±10.1	0.53

Data are presented as n (%), median (interquartile range) or mean±sd, unless otherwise stated. CRP: C-reactive protein; PCT: procalcitonin; P_a,CO₂: arterial carbon dioxide tension; P_a,O₂: arterial oxygen tension. p-values in bold are statistically significant.