Initial suction drainage decreases severe postoperative complications after pancreatic trauma: A cohort study

Figure 4 Relative risk for the primary outcomes in prespecified subgroups. The forest plot presents, for each subgroup, the relative risk of severe complications between different drain types by a square and its 95% confidence interval (CI) by a horizontal line. On the left side of the figure, the subgroup sample size by drain type is presented with the corresponding severe complication rate. The right side of the figure lists the relative risk and its 95%CI; the x-axis of the plot is the risk estimate of severe complications. The last column shows the P values for relative risk interactions between subgroups. Subgroup-specific relative risk was derived from modified Poisson regression. PG: Passive gravity; NPI: Negative pressure irrigation; BMI: Body mass index; ISS: Injury severity score; CI: Confidence interval.