The risk of bladder cancer in patients with urinary calculi: a meta-analysis

The objective of this meta-analysis was to evaluate the association between a history of urinary calculi (UC) and the risk of bladder cancer (BC). A literature search was performed from inception until July 2017. Studies that reported odds ratios (OR), relative risks or hazard ratios comparing the risk of BC in patients with the history of UC vs those without the history of UC were included. Pooled odds ratios and 95% confidence interval (CI) were calculated using a random-effect or fixed-effect method. Thirteen studies were included in our analysis to assess the association between a history of UC and risk of BC. The pooled OR of BC in patients with UC was 1.87 (95% CI, 1.45-2.41). Bladder calculi [OR, 2.17 (95% CI, 1.52-3.08)] had a higher risk of BC than kidney calculi [OR, 1.39 (95% CI, 1.06-1.82)]. The subjects had a history of UC that was associated with increased BC risk both in males [OR, 2.04 (95% CI, 1.41-2.96)] and in females [OR, 2.99 (95% CI, 2.37-3.76)]. The subgroup analysis demonstrated that UC increasing risk of BC both in case-control studies [OR, 1.75 (95% CI, 1.25-2.45)] and cohort studies [OR, 2.27 (95% CI, 1.55-3.32)]. The pooled OR of BC risk in patients with UC were 1.60 (95% CI, 1.15-2.24) in America, 1.36 (95% CI, 1.14-1.64) in Europe and 3.05 (95% CI, 2.21-4.21) in Asia, respectively. Our study demonstrates a significant increased risk of BC in patients with prior UC. This finding suggests that a history of UC is associated with BC and may impact clinical management and cancer surveillance. Further studies still needed to confirm the findings.