A meta-analysis was performed using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) Protocols. 
PRISMA
Three databases (PubMed, EMBASE and the Cochrane Library) were searched for articles containing data on BMI, disease severity and mortality rate for AP. 
PubMed
Three databases (PubMed, EMBASE and the Cochrane Library) were searched for articles containing data on BMI, disease severity and mortality rate for AP. 
EMBASE
Three databases (PubMed, EMBASE and the Cochrane Library) were searched for articles containing data on BMI, disease severity and mortality rate for AP. 
Cochrane Library