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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

Funnel plot.Funnel plot for evaluation of publication bias in the included studies on the association between serum IL-6 concentrations and COPD. COPD, chronic obstructive pulmonary disease; SMD, standard mean difference.
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fig-5: Funnel plot.Funnel plot for evaluation of publication bias in the included studies on the association between serum IL-6 concentrations and COPD. COPD, chronic obstructive pulmonary disease; SMD, standard mean difference.

Mentions: Egger’s test showed a publication bias in the overall meta-analysis (P < 0.00001), and the shape of the funnel plot was asymmetrical (Fig. 5), and so as the subgroup analysis of participants without major comorbidities. This might be explained by the presence of a language bias, inflated estimates by a flawed methodological design in smaller studies, lack of small trials with opposite results as well as the ethnicity difference since two of the studies, Walter et al. (2008) (from the UK) and Yende et al. (2006) (from the USA) possess largest cohort size. However, there was no significant evidence of publication bias among mild-moderate COPD versus controls (P = 0.231), severe-very severe COPD versus healthy controls (P = 0.137), and mild-moderate COPD versus severe-very severe COPD (P = 0.769).


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)

Funnel plot.Funnel plot for evaluation of publication bias in the included studies on the association between serum IL-6 concentrations and COPD. COPD, chronic obstructive pulmonary disease; SMD, standard mean difference.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig-5: Funnel plot.Funnel plot for evaluation of publication bias in the included studies on the association between serum IL-6 concentrations and COPD. COPD, chronic obstructive pulmonary disease; SMD, standard mean difference.
Mentions: Egger’s test showed a publication bias in the overall meta-analysis (P < 0.00001), and the shape of the funnel plot was asymmetrical (Fig. 5), and so as the subgroup analysis of participants without major comorbidities. This might be explained by the presence of a language bias, inflated estimates by a flawed methodological design in smaller studies, lack of small trials with opposite results as well as the ethnicity difference since two of the studies, Walter et al. (2008) (from the UK) and Yende et al. (2006) (from the USA) possess largest cohort size. However, there was no significant evidence of publication bias among mild-moderate COPD versus controls (P = 0.231), severe-very severe COPD versus healthy controls (P = 0.137), and mild-moderate COPD versus severe-very severe COPD (P = 0.769).

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