Assessment of pure red cell aplasia in US dialysis patients: the limits of the Medicare data.
BACKGROUND
A report of neutralizing antibodies to recombinant human erythropoietin (rHuEPO) in European dialysis patients raised concerns that US dialysis patients may be at similar risk. We investigated the frequency of diagnosis codes that include pure red cell aplasia (PRCA) in the Medicare end-stage renal disease data.


METHODS
Medicare claims data were used to identify incident dialysis patients from 1995 through 1999 aged 67 years or older who did not have a diagnosis code for aplastic anemia (AA; which includes PRCA) or were not administered rHuEPO before dialysis therapy initiation. Patients were assessed for complicating conditions, rHuEPO dose, hematocrit level, blood transfusion, bone marrow testing, and AA diagnosis (maximal follow-up, 13 months).


RESULTS
Of 101,782 patients eligible for study, 9,896 patients had diagnosis codes for AA after dialysis therapy initiation, 3,894 patients underwent bone marrow tests (required for PRCA diagnosis), 19 patients had diagnosis codes for AA based on bone marrow examination and no other complicating conditions, and 5 patients were administered blood transfusion in 1 or more months during follow-up, of whom only 1 patient had persistent low hematocrit levels while being administered rHuEPO and blood transfusion. This latter patient was identified from a total of 101,782 patients, or 70,706.75 person-years of rHuEPO exposure.


CONCLUSIONS
Diagnosis codes in the Medicare data are inadequate for the conclusive study of PRCA in US dialysis patients. Despite limitations of this study, it appears that few cases of rHuEPO-associated PRCA have occurred in US Medicare dialysis patients. Additional investigation is needed to determine whether apparent differences between US complication rates and those elsewhere result from differences in the manufacturing and/or use of erythropoietin products.
Collins
Allan J
AJ
Nephrology Analytical Services, Minneapolis Medical Research Foundation, Minneapolis, MN 55404, USA. acollins@nephrology.org
Li
Shuling
S
Adamson
John W
JW
Gilbertson
David T
DT
D000368:Aged; D000369:Aged, 80 and over; D001803:Blood Transfusion; D001856:Bone Marrow Examination; D004921:Erythropoietin / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D006400:Hematocrit; D006801:Humans; D038801:International Classification of Diseases; D007676:Kidney Failure, Chronic / Q000628:therapy; D008297:Male; D006278:Medicare / Q000706:statistics & numerical data*; D011994:Recombinant Proteins; D012010:Red-Cell Aplasia, Pure / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology / Q000628:therapy; D006435:Renal Dialysis / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology
D011994:Recombinant Proteins; D004921:Erythropoietin