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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 disease severity.Forrest plot of subgroup studies in the meta-analysis that investigated the association between serum IL-6 concentrations and pulmonary functions of COPD, 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-4: Forest plot for subgroup analysis by disease severity.Forrest plot of subgroup studies in the meta-analysis that investigated the association between serum IL-6 concentrations and pulmonary functions of COPD, using a random-effects model. COPD, chronic obstructive pulmonary disease; SD, standard difference; SMD, standard mean difference; CI, confidence interval.

Mentions: Thirteen studies had subgroups according to smoking status, body mass index (BMI) and COPD severity. We only evaluated IL-6 levels by severity of COPD. COPD was defined as post-bronchodilator forced expiratory volume in one second (FEV1)/(forced vital capacity) (FVC) <70%. Depending on whether FEV1 was <50% predicted (GOLD stage 3–4) or >50% (GOLD stage 1–2) we called it severe–very severe COPD and mild-moderate COPD (GOLD stage 1–2) respectively. Nine studies showed data including mild-moderate and/or severe-very severe COPD (de Moraes et al., 2014; Foschino Barbaro et al., 2007; Gagnon et al., 2014; Hacker et al., 2009; He et al., 2010; Palange et al., 2006; Uzum et al., 2014; Vogiatzis et al., 2007; Yasuda et al., 1998) and five of them compared mild-moderate with severe-very severe COPD (de Moraes et al., 2014; Hacker et al., 2009; He et al., 2010; Uzum et al., 2014; Yasuda et al., 1998). We compared mild-moderate COPD and severe-very severe COPD with healthy controls, respectively. When compared mild-moderate COPD with healthy controls, we chose data from studies that included COPD patients of GOLD stage 1, GOLD stage 2 or GOLD stage 1 and 2, similarly with the severe-very severe group. It was found that COPD patients with an FEV1 either <50% predicted or >50% predicted had increased IL-6 concentrations compared with healthy control subjects (SMD = 0.77, 95% CI [0.48–1.05], P < 0.00001; I2 = 29%, P = 0.19; SMD = 1.01, 95% CI [0.43–1.59], P = 0.0006; I2 = 77%, P = 0.0007, respectively; Fig. 4). Another subgroup analysis compared the difference between mild-moderate and severe-very severe COPD patients, but no statistically significant result was seen (SMD = − 0.1, 95% CI [−0.65–0.44], P = 0.71; I2 = 73%, P = 0.005; Fig. 4).


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 disease severity.Forrest plot of subgroup studies in the meta-analysis that investigated the association between serum IL-6 concentrations and pulmonary functions of COPD, 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-4: Forest plot for subgroup analysis by disease severity.Forrest plot of subgroup studies in the meta-analysis that investigated the association between serum IL-6 concentrations and pulmonary functions of COPD, using a random-effects model. COPD, chronic obstructive pulmonary disease; SD, standard difference; SMD, standard mean difference; CI, confidence interval.
Mentions: Thirteen studies had subgroups according to smoking status, body mass index (BMI) and COPD severity. We only evaluated IL-6 levels by severity of COPD. COPD was defined as post-bronchodilator forced expiratory volume in one second (FEV1)/(forced vital capacity) (FVC) <70%. Depending on whether FEV1 was <50% predicted (GOLD stage 3–4) or >50% (GOLD stage 1–2) we called it severe–very severe COPD and mild-moderate COPD (GOLD stage 1–2) respectively. Nine studies showed data including mild-moderate and/or severe-very severe COPD (de Moraes et al., 2014; Foschino Barbaro et al., 2007; Gagnon et al., 2014; Hacker et al., 2009; He et al., 2010; Palange et al., 2006; Uzum et al., 2014; Vogiatzis et al., 2007; Yasuda et al., 1998) and five of them compared mild-moderate with severe-very severe COPD (de Moraes et al., 2014; Hacker et al., 2009; He et al., 2010; Uzum et al., 2014; Yasuda et al., 1998). We compared mild-moderate COPD and severe-very severe COPD with healthy controls, respectively. When compared mild-moderate COPD with healthy controls, we chose data from studies that included COPD patients of GOLD stage 1, GOLD stage 2 or GOLD stage 1 and 2, similarly with the severe-very severe group. It was found that COPD patients with an FEV1 either <50% predicted or >50% predicted had increased IL-6 concentrations compared with healthy control subjects (SMD = 0.77, 95% CI [0.48–1.05], P < 0.00001; I2 = 29%, P = 0.19; SMD = 1.01, 95% CI [0.43–1.59], P = 0.0006; I2 = 77%, P = 0.0007, respectively; Fig. 4). Another subgroup analysis compared the difference between mild-moderate and severe-very severe COPD patients, but no statistically significant result was seen (SMD = − 0.1, 95% CI [−0.65–0.44], P = 0.71; I2 = 73%, P = 0.005; Fig. 4).

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