LGALS3 and chronic obstructive pulmonary disease: Since four of them reported the difference of galectin-3 between cases and controls according to the disease status of COPD (AECOPD or stable COPD) [20, 21, 23, 25], these datasets were included independently, and the sample sizes of the control groups were equally split to avoid unit-of-analysis errors as detailed in the Cochrane Handbook [28].