Prevalence of anemia and chronic kidney disease in cancer patients: clinical significance for 1-year mortality

Prevalence of anemia, stratified by severity grades, and chronic kidney disease (CKD) was studied in cancer patients receiving chemotherapy. In addition, their relevance to 1-year survival was estimated. We investigated the demographics and clinical findings of 231 cancer patients (male : 142, female : 89) who were admitted to the Division of Chemotherapy at the Cancer and Infectious Disease Center, Tokyo Metropolitan Komagome Hospital between April and September, 2008. Mean age was 63.6 +/- 12.7 years. Anemia was defined as a hemoglobin (Hb)level less than 12 g/dL and the anemia severity grades were classified according to the Anemia Toxicity Scales. Estimated glomerular filtration rate was calculated based on the formula of the Modification of Diet in Renal Disease modified for the Japanese. CKD was defined as stage 3 or more according to the K/DOQI criteria. To assess the clinical relevance of anemia and CKD to 1-year survival, we drew Kaplan-Meier curves, stratifying patients according to the anemia severity grades and the presence or absence of CKD. The joint impact of anemia grades and presence of CKD on 1-year mortality was assessed using the Cox proportional hazard analysis, adjusted for age and gender. Prevalence of anemia was 81% : 6.9% for grade 4 (Hb < 6.5 g/dL); 13.9% for grade 3(6.5 = Hb < 8.0 g/dL); 29.0% for grade 2 (8.0 = Hb < 10.0 g/dL); 31.2% for grade I (10.0 = Hb < 12.0 g/dL) and 19.0% for non-anemia cases. Prevalence of CKD was 25%. Survival probability of the overall or non-CKD cancer patients with anemia severity > or = grade 2 significantly decreased, as compared to that with no anemia. Survival probability of patients with CKD significantly decreased, as compared to that with no CKD. Statistically, the hazard ratio of mortality for patients with both grade 4-anemia and CKD was 14-fold higher than that for patients with neither anemia nor CKD. In conclusion, the prevalence of anemia and CKD were unexpectedly high in cancer patients. The combination of high-grade anemia and CKD is likely to be a significant risk factor for 1-year mortality of these patients.