Preoperative Anemia and Low Hemoglobin Level Are Associated With Worse Clinical Outcomes in Patients With Bladder Cancer Undergoing Radical Cystectomy: A Meta-Analysis
A meta-analysis was performed to synthesize currently available evidence and determine the association between preoperative anemia/hemoglobin level and prognosis of patients undergoing radical cystectomy. Seventeen studies were included, and the results showed that preoperative anemia and low hemoglobin level are associated with increased all-cause mortality, cancer-specific mortality, and disease recurrence.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.