Nine-Year Follow-Up of Interleukin 6 in Chronic Obstructive Pulmonary Disease – Complementary Results from Previous Studies

Figures & data

Table 1 Evolution of Inflammatory Profile at Baseline, After Three and Nine Years

Variables	Baseline (n = 33)	After Three Years (n = 33)	After Nine Years (n = 33)	p value
IL-6 (pg/mL)	0.5 (0.2–0.9)	2.3 (0.9–4.5)	5.2 (3.3–8.5)	<0.001
Lymphocytes (10^9/L)	2.1 (1.6–2.4)	1.9 (1.5–2.1)	1.4 (1.2–2.2)	0.10
Neutrophils (1000/mm^3)	4.1 (3.4–4.7)	4.2 (3.4–6.2)	3.8 (3–5)	0.25
Leukocytes (1000/mm^3)	6.5 (6.1–8.4)	7.1 (5.4–9.2)	6.5 (5.2–7.9)	0.32
N/L ratio	2.0 (1.5–2.3)	2.4 (1.8–2.9)	2.5 (1.5–3.3)	0.14

Notes: Values presented as mean ± standard deviation or median (quartiles 25–75). Mixed model; p < 0.05.

Abbreviations: IL-6, interleukin-6; N/L, neutrophils/lymphocytes.

Figure 1 IL-6 distribution of the population studied at baseline.

Figure 2 Kaplan–Meier mortality curve in relation to patients with IL-6 ≥ or < 3.1pg/mL.

Figure 3 Kaplan–Meier mortality curve in relation to patients with IL-6 ≥ or < 2.3pg/m.

Table 2 Assessment of IL-6 as a Time Dependent Covariate in Cox Regression Analysis

Parameter	Parameter Estimate	Standard Error	Chi-Square	P value	Hazard Ratio
Age, year	−0.07069	0.04440	2.5352	0.1113	0.932
Male gender	−0.16364	0.56907	0.0827	0.7737	0.849
BODE Index, class	0.12288	0.14311	0.7373	0.3905	1.131
Comorbidities, score	0.84229	0.31803	7.0144	0.0081	2.322
Exacerbations, n	0.29959	0.22177	1.8248	0.1767	1.349
SpO2, %	0.03991	0.07682	0.2699	0.6034	1.041
IL-6, pg/mL	0.02757	0.07842	0.1236	0.7252	1.028

Note: p < 0.05.

Abbreviations: BODE, body mass index, airflow obstruction, dyspnea and exercise capacity; Exacerbations, number of exacerbations in three first years; SpO2, pulse oximeter; IL-6, interleukin-6.