Preoperative Anemia and Low Hemoglobin Level Are Associated With Worse Clinical Outcomes in Patients With Bladder Cancer Undergoing Radical Cystectomy: A Meta-Analysis

Purpose: The aim of this study was to determine the effect of preoperative anemia status and hemoglobin level on clinical outcomes in patients with bladder cancer undergoing radical cystectomy.

Materials and methods: A systematic review of literature with meta-analyses of predefined outcomes based on a search of PubMed and EMBASE was performed. Hazard ratios (HRs) measuring the association between preoperative anemia/hemoglobin and all-cause mortality, cancer-specific mortality, and disease recurrence were calculated with random effects model. Study heterogeneities were quantified by I² tests. Publication bias was assessed with funnel plots.

Results: A total of 17 studies evaluating the impact of preoperative anemia status (categorical, 11 studies) and hemoglobin level (continuous, 7 studies) on clinical outcomes were included. The cutoff value of anemia varied among studies (10.5-13.5 g/dL for male, 10.5-13.4 g/dL for female). Meta-analyses showed that compared with non-anemia, anemia was associated with increased all-cause mortality (HR, 1.75; 95% confidence interval [CI], 1.48-2.05; P < .00001; I² = 30%), cancer-specific mortality (HR, 1.80; 95% CI, 1.45-2.25; P < .00001; I² = 26%), and disease recurrence (HR, 1.37; 95% CI, 1.16-1.62; P = .0002; I² = 9%). Meta-analyses showed that higher level of hemoglobin was associated with decreased all-cause mortality (HR, 0.90; 95% CI, 0.87-0.92; P < .00001; I² = 13%), cancer-specific mortality (HR, 0.90; 95% CI, 0.85-0.95; P = .0003; I² = 61%), and disease recurrence (HR, 0.95; 95% CI, 0.91-0.99; P = .01; I² = 53%). No obvious publication bias was observed.

Conclusions: Preoperative anemia and low hemoglobin level are associated with earlier recurrence and shorter survival of patients with bladder cancer undergoing radical cystectomy. However, well-designed prospective studies with large sample size and limited confounding factors are needed to confirm and update our findings.