Background: Recently, numerous studies have shown that pretreatment serum albumin can be closely associated with the prognosis of patients with bladder cancer (BC). However, the conclusions regarding this issue are still conflicting. Hence, in this study, we performed a systematic review and meta-analysis to determine the prognostic significance of pretreatment serum albumin in BC patients.
Materials and methods: A systematic search was carried out in PubMed, Embase, and Web of Science. A total of 16 studies involving 13,917 patients were included in the current meta-analysis. hazard ratios (HRs) and 95% CIs were pooled to assess the intensity of association. Moreover, heterogeneity, sensitivity analysis and publication bias were explored. All statistical analyses were conducted by STATA 12.0.
Results: Our results suggested that a decreased pretreatment serum albumin level was closely related to a worse overall survival (HR 1.88, 95% CI 1.43, 2.48; P<0.01) and cancer-specific survival (HR 1.65, 95% CI 1.08, 2.52; P =0.02). In addition, from the results of this meta-analysis, it was also observed that a lower pretreatment serum albumin level was linked to higher incidence of postoperative 30-day complication (odds ratio [OR] 1.41, 95% CI 1.03, 1.91; P =0.03) and 90-day mortality (OR 2.51, 95% CI 1.82, 3.48; P <0.01). Furthermore, these findings were demonstrated to be reliable by our sensitivity and subgroup analysis stratified by ethnicity, analysis type, and cutoff value. 
Conclusion: Our results revealed that a lower pretreatment serum albumin level yields a poor long-term prognosis and increases the risks of postoperative complication and mortality in BC patients and can be applied to risk stratification and individualized therapy in BC patients.
Keywords: albumin, prognosis, mortality, bladder cancer, meta-analysis