Association between Serum Tumour Necrosis Factor-α Concentrations and Chronic Obstructive Pulmonary Disease

Tumour necrosis factor-α (TNF-α) 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 a meta-analysis to assess the association between serum TNF-α concentration and COPD. PubMed and Embase were searched for eligible studies. Data were extracted and standard mean differences (SMDs) and 95% confidence intervals (CI) were calculated. Thirty-three studies were included in the meta-analysis. The serum TNF-α concentrations were higher in patients with stable COPD than healthy controls (SMD = 0.64 pg/ml, 95%CI 0.43, 0.86). COPD patients with normal to high body mass index (BMI) and low BMI had increased TNF-α concentration compared with healthy controls (SMD = 1.14 pg/ml, 95%CI 0.36, 1.92; SMD = 1.62 pg/ml, 95%CI 0.89, 2.35 respectively). There was notable significance in serum TNF-α level between underweight and normal weight COPD patients (SMD = 0.68, 95%CI 0.43, 0.92). The meta-analysis indicates that patients with stable COPD have higher serum TNF-α concentration than healthy controls, and the higher circulating TNF-α levels in COPD patients with weight loss may suggest its valuable role in the evaluation of systemic inflammatory responses in stable COPD patients.