Preoperative Anemia or Low Hemoglobin Predicts Poor Prognosis in Gastric Cancer Patients: A Meta-Analysis

Background. The prognostic value of preoperative anemia in gastric cancer remains unclear. Therefore, the purpose of the present study is to evaluate the prognostic value of preoperative anemia in gastric cancer. Methods. We searched Embase and PubMed databases for relevant studies from inception to March 2018. The prognostic value of preoperative anemia in gastric cancer was determined by calculating the hazard ratio (HR) and the corresponding 95% confidence interval (CI) as effect measures. A random effect model was used in cases in which there was significant heterogeneity; otherwise, a fixed effect model was used. Statistical analyses were performed using Stata software. Results. Seventeen studies involving 13,154 gastric cancer patients were included. The estimated rate of preoperative anemia was 36% (95%CI=27-44%). The overall survival of preoperative anemia was poor (HR=1.33, 95%CI=1.21-1.45). Moreover, disease-free survival was significantly lower in patients with preoperative anemia compared with those without this condition (HR=1.62, 95%CI=1.13-2.32). These findings were corroborated by the results of subgroup analyses. Conclusions. The results indicate that preoperative anemia predicts poor prognosis in gastric cancer, including overall survival and disease-free survival. Therefore, preoperative anemia may be a convenient and cost-effective blood-derived prognostic marker for gastric cancer.