OBJECTIVE: Patients with CKD typically have progressive loss of kidney function, eventually leading to anemia. Anemia of pCKD may contribute to worsening of health, resulting in higher costs to employers. This analysis quantifies the economic burden of untreated anemia in pCKD patients from an employer's perspective. METHODS: A retrospective analysis was conducted using anonymous health and disability claims from 31 U.S. employers between January 1998 and January 2005 from approximately 5 million individuals. A total of 7258 pCKD patients with at least two CKD claims less than 90 days apart prior to dialysis, not receiving anemia therapy with erythropoietic-stimulating agents and with no history of organ transplant were identified. Of these, 1534 (21%) with at least 2 anemia ICD-9 diagnosis claims were classified as anemic. The anemia period was from the first anemia claim to disenrollment, organ transplant, or study end. The remaining 5724 patients provided the non-anemia reference period. To isolate costs specific to anemia, multivariate regression analyses were conducted to control for liver cirrhosis, hypertension, chemotherapy, Charlson Comorbidity Index, age, sex, health plan, and region. Employers' costs comprised direct medical/indirect productivity (short- and long-term disability, sick leave). RESULTS: Univariate and multivariate analyses indicated that untreated anemia was associated with statistically significant increases in direct and indirect costs. The univariate incremental monthly direct and indirect costs of untreated anemia were $1344 ($2401 untreated anemic vs. $1057 non-anemic, p<0.001), a 2.3:1 cost ratio, and $271 ($620 vs. $349, p<0.001), a 1.8:1 cost ratio. Multivariate analyses confirmed that incremental monthly direct and indirect costs for untreated anemia remained significant at $855 (p<0.001), a 1.8:1 cost ratio, and $164 (p<0.001), a 1.5:1 cost ratio. CONCLUSIONS: Untreated anemia in pCKD patients was associated with significantly higher direct and indirect costs to employers. Studies are needed to evaluate cost-effectiveness of treating anemia of pCKD.