Association of matrix metalloproteinase-12 polymorphisms with chronic obstructive pulmonary disease risk: A protocol for systematic review and meta analysis.

BACKGROUND Chronic obstructive pulmonary disease (COPD) is a multifactorial disease with gene-environment interaction leading to airflow limitation through the respiratory tract. Reports on the association of matrix metalloproteinase 12 (MMP-12) polymorphisms with COPD have been controversial. A new systematic evaluation which could examine whether MMP-12 mutations are associated with the susceptibility to COPD is needed. METHODS We will search PubMed, EMBASE, Web of Science, China National Knowledge Infrastructure and Google Scholar to obtain eligible case-control studies for meta-analysis. The time is limited from the construction of the library to July 2020. Two investigators systematically will extract relevant data within those included studies.The odds ratio and 95% confidence intervals will be used to assess the genetic association between the allelic, dominant and recessive models of MMP-12 gene polymorphisms and COPD risk. Stata 12.0 software and Revman 5.3 will be adopted for statistical analysis. This protocol reported under the Preferred Reporting ltems for Systematic Reviews and Meta-Analyses Protocols statement. RESULTS This study will provide a better understanding of the association between MMP-12 polymorphisms and COPD risk. CONCLUSION Publishing this protocol will minimise the possibility of bias due to post hoc changes to the analysis protocol.