The Association of obesity with vascular complications after liver transplantation

Background: Because of the growing number of obese patients undergoing liver transplantation (LT), it is important to investigate the impact of obesity on post-transplant outcomes. Vascular complications are rare, but serious causes of morbidity and mortality after LT. It is not known if pre-transplant obesity is associated with an increased incidence of post-LT vascular complications. Methods: Medline, Embase, and Cochrane Library databases were searched in September 2017. The primary outcome was the impact of obesity on the vascular complication rate in adult LT recipients. Survival and biliary complications rates were also analyzed. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated to compare pooled data between groups with a body mass index (BMI) >= 30 kg/m(2) and < 30 kg/m(2). Results: Six retrospective cohort studies with a total of 987 patients with a BMI >= 30 kg/m(2) (high BMI group) and 2911 patients with a BMI < 3 0 kg/m(2) (control group) were included in the analysis. All studies had Newcastle-Ottawa Scale scores >= 4. The vascular complication rates were similar between the high BMI group and control group (RR = 1.13, 95% CI: 0.87-1.47, P = 0.27), as were the patient survival, graft survival, and biliary complication rates. In subgroup analysis, there was no difference in the vascular complication rates between BMI >= 35 vs. BMI < 25 kg/m(2); BMI 30-35 vs. BMI 18-25 kg/m(2); BMI >= 30 vs. BMI 18-25 kg/m(2); and BMI >= 35 vs. BMI < 35 kg/m(2). No difference was found in subgroup analysis when BMI was adjusted for ascites. However, recipients whose primary disease was alcoholic liver disease, those with a BMI >= 30 kg/m(2) had higher incidence of vascular complications than those with a BMI < 30 kg/m(2) (RR = 1.55, 95% CI: 1.07-2.25, P = 0.02). Conclusions: BMI does not affect incidence of vascular complications after LT. High pre-transplant BMI is not a risk factor for patient survival and biliary complications after LT.