Background: Large observational studies examining the association between anemia and "hard" clinical outcomes are rare in patients with chronic kidney disease (CKD). Methods: We used the General Medicare 5% Denominator Files to identify patients aged 67 years or more with CKD on December 31, 1999. Outcomes in the ensuing 2 years were compared in patients with and those without anemia (entry period, 1998-1999; follow-up period, 2000-2001). Results: Of 41,522 CKD patients identified, 49.0% had claims of anemia diagnosis. The factors associated (p < 0.0001) with anemia included older age, female gender, black race, and all 10 comorbid conditions studied; adjusted odds ratios (ORs) exceeded 1.5 for age 80 years old or older (OR, 1.54 compared to <70 years), for black race (OR, 1.52), and for co-existing diagnoses of congestive heart failure (OR, 1.64), gastrointestinal bleeding (OR, 3.65), and liver disease (OR, 2.16). During the follow-up period, outcome event rates (expressed per 1000 patient-years) were as follows: renal replacement therapy, 23.5; death, 186.4; congestive heart failure, 390.0; atherosclerotic vascular disease, 410.5; and first hospitalization, 552.6. Using proportional hazards modeling, the presence of anemia was associated (p < 0.0001) with the following adjusted hazards ratios: atherosclerotic vascular disease, 1.09; congestive heart failure, 1.14; renal replacement therapy, 2.61 and death, 1.40. Conclusion: A diagnosis of anemia is present in nearly half of all patients with CKD, aged 67 years or more, a group at very high risk of cardiovascular disease, hospitalization, end-stage renal disease, and death. Anemia is associated with each of these events.
Bibliographical noteFunding Information:
This research was supported by an unrestricted research grant from Amgen Inc., Thousand Oaks, California, USA. The authors thank Dana D. Knopic and James Kaufmann, Ph.D., for assistance with manuscript preparation and editing, respectively.
Copyright 2008 Elsevier B.V., All rights reserved.
- Chronic kidney disease