Anemia and Incident End-Stage Kidney Disease

Background CKD progression can be a cause and potentially a consequence of anemia. Previous studies suggesting that anemia is associated with CKD progression have not used methodologic approaches to address time-dependent confounding. Methods We evaluated the association of anemia (defined using World Health Organization criteria of hemoglobin <12 g/dl in women and <13 g/dl in men) with incident ESKD and all-cause death in individuals with CKD using data from the Chronic Renal Insufficiency Cohort Study. Marginal structural models were used to account for time-dependent confounding. Results Among 3919 participants, 1859 (47%) had anemia at baseline. Over median follow-up of 7.8 years, we observed 1010 ESKD events and 994 deaths. In multivariable analyses, individuals with anemia had higher risk for ESKD compared with those without (HR, 1.62; 95% CI, 1.24 to 2.11). In stratified analyses, the increased risk for incident ESKD with anemia was observed in males (HR, 2.15; 95% CI, 1.53 to 3.02) but not females (HR, 1.20; 95% CI, 0.82 to 1.78). The association between anemia and ESKD was significant among all racial/ethnic groups except non-Hispanic blacks (non-Hispanic white, HR, 2.16; 95% CI, 1.53 to 3.06; Hispanic, HR, 1.92; 95% CI, 1.04 to 3.51; others, HR, 2.94; 95% CI, 1.16 to 7.44; non-Hispanic black, HR, 1.39; 95% CI, 0.95 to 2.02). There was no association between anemia and all-cause death. Conclusions In this cohort, anemia was independently associated with increased risk for incident ESKD. Future work is needed to evaluate the mechanisms by which anemia leads to CKD progression as well as the effect of novel therapeutic agents to treat anemia.