1. BACKGROUND Incidence of Myelodysplastic Syndromes in the United States Medicare Population  The myelodysplastic syndromes (MDS) are a heterogeneous group of marrow failure diseases associated with serious morbidity with the additional risk of leukemia transformation.  The disease course may be indolent or aggressive.  MDS is a diagnosis of exclusion. Most de novo patients are symptomatic or present with symptoms of anemia  The incidence of these disorders in the United States (US) remain largely conjecture with one available study assessing MDS incidence rates based on 18 Surveillance, Epidemiology, and End Results (SEER) areas.  Though a common cause of marrow failure in the elderly population, the incidence of MDS in the US elderly population is unknown. METHODS Approach  This retrospective, observational, cohort study was conducted using administrative claims data from a nationally representative sample of Medicare patients, comprising 1.7 million members between Jan 2003 to Dec 2003. Data Source  The Medicare Standard Analytic File (SAF) is a randomly-selected 5% sample of all Medicare beneficiaries.  Medicare beneficiaries are individuals ≥65 years, eligible for disability, and/or have end-stage renal disease.  Data from Jan 2003 to Dec 2003 were included in the analysis.  The dataset is fully de-identified and HIPAA-compliant.  The SAF includes claims across different settings of care, such as inpatient, outpatient, physician care, skilled nursing facilities, home health and hospice, durable medical equipment. A denominator file provides demographic and coverage information about the beneficiaries in the dataset. Identification of Study Population  The International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9) code 238.7 was used to define patients with primary diagnoses of MDS in 2003.  To ensure the study cohort identified represented the incidence population, patients diagnosed with myeloid leukemia (ICD-9-CM codes 205.0, 205.1) or anemias of known causes (ICD-9-CM codes 281, 282, 283, and 284) in 2002 were excluded.  The incidence of MDS was described by age, gender, and race (Caucasian, African-American, Hispanic/Latino, and Others). RESULTS  We identified 5,594 MDS patients out of approximately 1.7 million patients in the Medicare SAF in 2003.  After removing 2,516 patients with myeloid leukemia or anemias of known causes in 2002, we obtained a cohort of 3,078 patients with newly-diagnosed MDS in 2003 (181 per 100,000).  Of these cases, 530 (17.2%) had a previous history of unexplained anemia, 172 (5.6%) prior chemotherapy or radiotherapy exposure, and 2,376 (77.2%) were de novo.  The median age of the Medicare sample was 76 years (range 24-98).  Among individuals aged 80, the incidences of MDS in the Medicare database were 92.6, 132.8, 199.2, 261.5 per 100,000, respectively, confirming the SEER findings of an age effect.  Age-adjusted incidence rates for MDS in 2003 were higher among males than females (201.7 per 100,000 in males vs. 165.7 per 100,000 in females, p<0.001).  Incidence rates varied by race (Caucasian 186.5, African-American 142.7, Hispanic/Latino 147.0, and Others 160.1 per 100,000, respectively). RESULTS (Continued) MDS Medicare beneficiariesMDS Incidence * (95% CI † ) Overall – n3,0781,700,249181(179-183) Age – n <60 yr 60-69 yr 70-79 yr >80 yr 193 689 1,125 1,067 208,493 518,869 564,795 408,092 92.6 132.8 199.2 261.5 (91.4-93.9) (131.9-133.7) (198.2-200.2) (260.2-262.9) Gender – n ‡ Male Female 1,442 1,632 715,070 985,179 201.7 165.7 (200.8-202.6) (165.0-166.4) Race – n ‡ Caucasian African-American Hispanic/Latino Others 2,711 226 53 84 1,453,306 158,427 36,064 52,452 186.5 142.7 147.0 160.1 (185.9-187.1) (141.0-144.4) (143.4-150.7) (157.0-163.3) Figure 2. MDS Incidence in the US Medicare 5% Random Sample, 2003 Medicare beneficiaries in 2003 = 1,700,249 Primary diagnoses of MDS in 2003 = 5,594 Newly-diagnosed MDS in 2003 = 3,078 Pre-existing diagnoses of MDS, myeloid leukemia or anemias of known causes in 2002 = 2,516 Previous history of unexplained anemia = 530 De Novo =2,376 Prior chemo- or radiotherapy exposure = 172 Figure 1. Identification of Study Population CONCLUSION  The MDS incidence of 181 per 100,000 in this Medicare database is higher than previously reported in the SEER project for comparable age groups.  The Medicare database is derived by physician impression of diagnoses rather than confirmed histology. Thus the higher incidence in this study may more closely reflect the true findings in an elderly population, many of whom may not undergo extensive diagnostic evaluations.  New ICD-9 codes introduced in October 2006 that stratify subtypes of MDS will facilitate future studies of incidence and prevalence patterns of MDS. REFERENCES 1. Ma X, Dose M, Raza A, Mayne ST. Myelodysplastic syndromes: incidence and survival in the United States. Cancer. 2007 Mar 7;109(8):1536-1542. 2. Greenberg PL, Young NS, Gattermann N. Myelodysplastic syndromes. Hematology Am Soc Hematol Educ Program. 2002;36-61. 3. Rollison DE, Hayat M, Smith M, Strom SS, Merritt WD, Ries L, Edwards BK, List AF. First Report of National Estimates of the Incidence of Myelodysplastic Syndromes and Chronic Myeloproliferative Disorders from the U.S. SEER Program. Blood (ASH Annual Meeting Abstracts), Nov 2006; 108:247. * Rates are per 100,000 per year † 95% CI indicates 95% confidence interval ‡ Age-adjusted rates P001 SL Goldberg 1 ; N Mody-Patel 2 ; N Warnock 3 1 Hackensack University Medical Center, Hackensack, NJ; 2 Novartis Pharmaceuticals, Florham Park, NJ; 3 Quorum Consulting, Inc., San Francisco, CA Funding for this study was provided by Novartis Pharmaceutical Corporation, Florham Park, NJ, USA Presented at the 9th International Symposium on Myelodysplastic Syndromes, Florence, Italy, May 16-19, 2007. Poster #P001. OBJECTIVE  The objective of this analysis is to describe the incidence of MDS in the US Medicare population using a national database.