Original StudyMortality and Vascular Events Among Elderly Patients With Chronic Myeloid Leukemia: A Retrospective Analysis of Linked SEER-Medicare Data

BackgroundTyrosine-kinase inhibitors (TKIs) can be associated with vascular events (VEs). The expected VE rates in patients with chronic myeloid leukemia (CML) are unknown. The present study examined the event rates and mortality among elderly patients with and without CML.Materials and MethodsLinked Surveillance, Epidemiology, and End Results cancer registry and Medicare claims data were used to identify patients aged ≥ 66 years with an incident (index) diagnosis of CML from 2004 to 2009. A comparison cohort of patients without cancer was matched 1:1 to the CML cohort. All patients were followed up from 12 months before the index diagnosis through death or December 31, 2010. The overall survival and rates of myocardial infarction (MI), stroke, pulmonary embolism (PE), and peripheral arterial disease (PAD) were analyzed.ResultsA total of 1466 patients with CML (mean age, 78 years; average follow-up period, 25 months) were identified and matched 1:1 to a noncancer cohort (mean age, 78 years; follow-up period, 42 months). Compared with the noncancer patients, those with CML had greater mortality (63% vs. 23% died during the follow-up period; median survival, 23 vs. > 84 months) and greater rates of MI (33.0 vs. 11.9 per 1000 person-years), stroke (83.2 vs. 43.0), PE (6.6 vs. 2.6), and PAD (92.1 vs. 59.3; P < .01 for all). Of the 15% of CML patients with TKI claims, 97% had received imatinib. The event rates were not elevated for TKI-treated patients compared with the overall group of patients with CML.ConclusionElderly patients with CML had greater mortality and greater rates of MI, stroke, PE, and PAD than did noncancer patients. The event rates were not elevated among the TKI-treated (primary imatinib) patients, suggesting that the VE risk in these patients with CML was driven primarily by the underlying factors associated with CML.