In the sub-group of studies using ATS guidelines for COPD diagnosis, we found that serum albumin concentrations were not significantly different between COPD patients and control subjects (SMD = −0.21, 95% CI –0.55 to 0.13, p < 0.124; I2 = 37.6%, p < 0.171). The gene discussed is ALB; the disease is chronic obstructive pulmonary disease.