Association between obesity and bladder cancer recurrence: A meta-analysis

Background: The association between obesity and bladder cancer prognosis is not well-defined. This meta analysis was performed to explore whether obesity is related to overall survival (OS) and bladder cancer recurrence. Methods: Relevant English-language studies were identified by searching PubMed (R) up to November 1, 2017. We pooled the hazard ratios (HR) and 95% confidence intervals (CIs) using a random effect model. Dose-response relationship, subgroup and sensitivity were also analyzed. Results: Eleven studies were included. Recurrence rate of bladder cancer was significantly greater in obese (HR = 1.76, 95% CI: 1.36-2.28) vs normal weight patients. Stratification analysis showed that females had higher recurrence risk than males (HR = 1.17, 95% CI: 1.05-1.31). Obesity was not significantly associated with bladder cancer OS (HR = 1.21, 95% CI: 0.97-1.52). Dose-response relationship analysis revealed a linear association between BMI and risk of recurrence. Each one kg/m2 increase in BMI was related to a 1.3% increased risk of bladder cancer recurrence (HR = 1.01, 95% CI = 1.01 to 1.02). Conclusions: This meta-analysis revealed that obesity may be a risk factor for bladder cancer recurrence.