Premorbid Obesity and Mortality in Patients With Pancreatic Cancer: A Systematic Review and Meta-analysis.

ABSTRACT

BACKGROUND & AIMS: Obesity is associated with an increased risk for pancreatic cancer, but it is unclear whether it affects mortality. We performed a systematic review and meta-analysis to assess the association between premorbid obesity and mortality from pancreatic cancer. METHODS: We performed a systematic search through January 2015 and identified studies of the association between premorbid obesity (at least 1 year prior to pancreatic cancer diagnosis) and pancreatic cancer-related mortality. We estimated summary adjusted hazard ratio (aHR) with 95% confidence interval (CI), comparing data from obese (body mass index [BMI] ≥30 kg/m(2)) and overweight subjects (BMI, 25.0-29.9 kg/m(2)) with those from individuals with a normal BMI (controls) by using random-effects model. RESULTS: We identified 13 studies (including 3 studies that pooled multiple cohorts); 5 studies included only patients with pancreatic cancer, whereas 8 studies evaluated pancreatic cancer-related mortality in cancer-free individuals at inception. In the meta-analysis, we observed increase in pancreatic cancer-related mortality among overweight (aHR, 1.06; 95% CI, 1.02-1.11; I(2) = 0) and obese individuals (aHR, 1.31; 95% CI, 1.20-1.42; I(2) = 43%), compared with controls; the association remained when we analyzed data from only subjects with pancreatic cancer. Each 1 kg/m(2) increase in BMI was associated with 10% increase in mortality (aHR, 1.10; 95% CI, 1.05-1.15) with minimal heterogeneity (I(2) = 0). In the subgroup analysis, obesity was associated with increased mortality in Western populations (11 studies; aHR, 1.32; 95% CI, 1.22-1.42) but not in Asia-Pacific populations (2 studies; aHR, 0.98; 95% CI, 0.76-1.27). CONCLUSIONS: In a systematic review and meta-analysis, we associated increasing level of obesity with increased mortality in patients with pancreatic cancer in Western but not Asia-Pacific populations. Strategies to reduce obesity-induced metabolic abnormalities might be developed to treat patients with pancreatic cancer.