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Association between serum interleukin-6 concentrations and chronic obstructive pulmonary disease: a systematic review and meta-analysis.

Wei J, Xiong XF, Lin YH, Zheng BX, Cheng DY - PeerJ (2015)

Bottom Line: Results.Conclusions.No evidence showing positive or negative association between IL-6 concentrations and the severity of pulmonary function impairment was found.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Respiratory Medicine, West China Hospital of Sichuan University , Chengdu, Sichuan , China.

ABSTRACT
Background. Interleukin-6 (IL-6) is an important pro-inflammatory cytokine and has been implicated to play a role in the systemic inflammation of patients with chronic obstructive pulmonary disease (COPD). We conducted this meta-analysis to assess the association between serum IL-6 concentrations and COPD. Methods. PubMed and Embase were searched for eligible studies. Data were extracted by two investigators (Wei J, Xiong XF) independently and analyzed using Review Manager 5.3 and STATA 12.0 software. Standard mean differences (SMDs) and 95% confidence intervals (CI) were calculated. Results. Thirty-three studies were included in this meta-analysis. The serum IL-6 concentrations were higher in patients with stable COPD than healthy controls (SMD = 0.65, 95% CI [0.51-0.79]). COPD patients without major comorbidities also showed higher IL-6 levels than healthy controls (SMD = 0.74, 95% CI [0.56-0.91]). COPD patients with an forced expiratory volume in one second (FEV1) of either <50% predicted or >50% predicted had increased IL-6 concentrations compared to healthy controls (SMD = 0.77, 95% CI [0.48-1.05], SMD = 1.01, 95% CI [0.43-1.59], respectively). The serum IL-6 concentrations between mild-moderate and severe-very severe COPD patient groups were not found to be significant (SMD = -0.1, 95% CI [-0.65-0.44]). Conclusions. This meta-analysis indicated that patients with stable COPD had higher serum IL-6 concentrations than healthy controls. No evidence showing positive or negative association between IL-6 concentrations and the severity of pulmonary function impairment was found. The correlation between IL-6 levels and pulmonary function was weak in different severities of stable COPD patients.

No MeSH data available.


Related in: MedlinePlus

Forest plot for subgroup analysis by comorbidities.Forrest plot of subgroup studies in the meta-analysis that investigated the association between serum IL-6 concentrations and COPD patients without major comorbid conditions, using a random-effects model. COPD, chronic obstructive pulmonary disease; SD, standard difference; SMD, standard mean difference; CI, confidence interval.
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fig-3: Forest plot for subgroup analysis by comorbidities.Forrest plot of subgroup studies in the meta-analysis that investigated the association between serum IL-6 concentrations and COPD patients without major comorbid conditions, using a random-effects model. COPD, chronic obstructive pulmonary disease; SD, standard difference; SMD, standard mean difference; CI, confidence interval.

Mentions: Among the 33 selected studies, 26 mentioned comorbidities in their inclusion or exclusion criteria, and seven studies had no information about comorbidities (Itoh et al., 2004; Jammes et al., 2008; Rabinovich et al., 2003; Tomoda et al., 2007; Van Helvoort et al., 2006; Walter et al., 2008; Ying et al., 2008). A total of 23 of the 26 studies excluded participants with some major comorbidities such as liver disease, renal insufficiency, collagen disease, sarcoidosis, ischemic heart disease, congestive cardiac failure, cor pulmonale, severe coronary artery disease, malignancy, systemic autoimmune or connective tissue disorders, or any other inflammatory or metabolic condition. We conducted another subgroup analysis only including those 23 studies without major comorbidities and compared IL-6 concentrations between cases and controls. The results also showed that the serum levels of IL-6 were higher in stable COPD patients than healthy controls (SMD = 0.74, 95% CI [0.56–0.91], P < 0.00001; I2 = 57%, P = 0.0004; Fig. 3) (Aaron et al., 2010; Bai et al., 2011; Bolton et al., 2007a; Bolton et al., 2007b; de Moraes et al., 2014; Debigare et al., 2003; Foschino Barbaro et al., 2007; Gale et al., 2011; Hacker et al., 2009; Hageman et al., 2003; He et al., 2010; Huertas et al., 2010; Ju & Chen, 2012; Karadag et al., 2008a; Karadag et al., 2008b; Koechlin et al., 2004; Oncel et al., 2010; Palange et al., 2006; Sabit et al., 2007; Uzum et al., 2014; Vogiatzis et al., 2007; Wang et al., 2014; Yasuda et al., 1998).


Association between serum interleukin-6 concentrations and chronic obstructive pulmonary disease: a systematic review and meta-analysis.

Wei J, Xiong XF, Lin YH, Zheng BX, Cheng DY - PeerJ (2015)

Forest plot for subgroup analysis by comorbidities.Forrest plot of subgroup studies in the meta-analysis that investigated the association between serum IL-6 concentrations and COPD patients without major comorbid conditions, using a random-effects model. COPD, chronic obstructive pulmonary disease; SD, standard difference; SMD, standard mean difference; CI, confidence interval.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4556145&req=5

fig-3: Forest plot for subgroup analysis by comorbidities.Forrest plot of subgroup studies in the meta-analysis that investigated the association between serum IL-6 concentrations and COPD patients without major comorbid conditions, using a random-effects model. COPD, chronic obstructive pulmonary disease; SD, standard difference; SMD, standard mean difference; CI, confidence interval.
Mentions: Among the 33 selected studies, 26 mentioned comorbidities in their inclusion or exclusion criteria, and seven studies had no information about comorbidities (Itoh et al., 2004; Jammes et al., 2008; Rabinovich et al., 2003; Tomoda et al., 2007; Van Helvoort et al., 2006; Walter et al., 2008; Ying et al., 2008). A total of 23 of the 26 studies excluded participants with some major comorbidities such as liver disease, renal insufficiency, collagen disease, sarcoidosis, ischemic heart disease, congestive cardiac failure, cor pulmonale, severe coronary artery disease, malignancy, systemic autoimmune or connective tissue disorders, or any other inflammatory or metabolic condition. We conducted another subgroup analysis only including those 23 studies without major comorbidities and compared IL-6 concentrations between cases and controls. The results also showed that the serum levels of IL-6 were higher in stable COPD patients than healthy controls (SMD = 0.74, 95% CI [0.56–0.91], P < 0.00001; I2 = 57%, P = 0.0004; Fig. 3) (Aaron et al., 2010; Bai et al., 2011; Bolton et al., 2007a; Bolton et al., 2007b; de Moraes et al., 2014; Debigare et al., 2003; Foschino Barbaro et al., 2007; Gale et al., 2011; Hacker et al., 2009; Hageman et al., 2003; He et al., 2010; Huertas et al., 2010; Ju & Chen, 2012; Karadag et al., 2008a; Karadag et al., 2008b; Koechlin et al., 2004; Oncel et al., 2010; Palange et al., 2006; Sabit et al., 2007; Uzum et al., 2014; Vogiatzis et al., 2007; Wang et al., 2014; Yasuda et al., 1998).

Bottom Line: Results.Conclusions.No evidence showing positive or negative association between IL-6 concentrations and the severity of pulmonary function impairment was found.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Respiratory Medicine, West China Hospital of Sichuan University , Chengdu, Sichuan , China.

ABSTRACT
Background. Interleukin-6 (IL-6) is an important pro-inflammatory cytokine and has been implicated to play a role in the systemic inflammation of patients with chronic obstructive pulmonary disease (COPD). We conducted this meta-analysis to assess the association between serum IL-6 concentrations and COPD. Methods. PubMed and Embase were searched for eligible studies. Data were extracted by two investigators (Wei J, Xiong XF) independently and analyzed using Review Manager 5.3 and STATA 12.0 software. Standard mean differences (SMDs) and 95% confidence intervals (CI) were calculated. Results. Thirty-three studies were included in this meta-analysis. The serum IL-6 concentrations were higher in patients with stable COPD than healthy controls (SMD = 0.65, 95% CI [0.51-0.79]). COPD patients without major comorbidities also showed higher IL-6 levels than healthy controls (SMD = 0.74, 95% CI [0.56-0.91]). COPD patients with an forced expiratory volume in one second (FEV1) of either <50% predicted or >50% predicted had increased IL-6 concentrations compared to healthy controls (SMD = 0.77, 95% CI [0.48-1.05], SMD = 1.01, 95% CI [0.43-1.59], respectively). The serum IL-6 concentrations between mild-moderate and severe-very severe COPD patient groups were not found to be significant (SMD = -0.1, 95% CI [-0.65-0.44]). Conclusions. This meta-analysis indicated that patients with stable COPD had higher serum IL-6 concentrations than healthy controls. No evidence showing positive or negative association between IL-6 concentrations and the severity of pulmonary function impairment was found. The correlation between IL-6 levels and pulmonary function was weak in different severities of stable COPD patients.

No MeSH data available.


Related in: MedlinePlus