Impact of Hypomethylating Agents on Cardiovascular Disease Risk Among Patients with Myelodysplastic Syndromes

Introduction:

The association between clonal hematopoiesis (CH) and cardiovascular disease (CVD) risk has drawn attention to cardiovascular outcomes in myelodysplastic syndromes (MDS). CVD accounts for 25% of deaths in MDS, potentially via CH-mediated accelerated atherosclerosis from inflammatory vascular responses. We previously demonstrated that MDS was independently associated with increased risk of CVD in older adults from SEER-Medicare. We subsequently hypothesized that treatment with hypomethylating agents (HMA) could reduce CVD risk by ameliorating CH clones and reducing the inflammation. In this study, we aimed to define the impact of HMA on incident cardiovascular events among older adults with MDS.

Methods:

We identified subjects ≥66 years diagnosed with MDS from 2007 to 2017 in SEER-Medicare. Exclusion criteria including lacking continuous Medicare parts A, B, and D, enrolled in HMO, or incomplete follow-up. Demographics included age, sex, race, rurality, socioeconomic quintile, marital status, and geographic region. Baseline CVD risk factors, defined from ICD-9/10 codes, included hypertension, hyperlipidemia, diabetes, atrial fibrillation, pre-existing cardiac disease, obesity, and smoking. MDS factors, defined using HCPCS codes, ICD-O-3 codes and prescription records, included MDS subtype and histologic risk stratification, transfusion dependence and treatment with hypomethylating agents (HMA), lenalidomide, or erythropoietin-stimulating agents (ESA) as time-varying variables. Incident CVD was defined as new myocardial infarction (MI) and/or ischemic stroke occurring after MDS diagnosis, using published ICD-9/10 algorithms. We controlled for confounding using 2 complementary analytic approaches. First, we assessed the association between HMA use and CVD using propensity score adjusted cause-specific competing risk Cox hazard models with death as competing risk, Second, we used a case-crossover design with conditional logistic regression, in which subjects with CVD served as their own controls, using a 3-month HMA treatment window and a control period 6 months prior to the incident event.

Results:

We identified a cohort of 15,227 eligible patients with MDS. Of these, 1,125 patients had an MI and/or ischemic stroke within 1 year before MDS diagnoses and were excluded. We analyzed 14,102 MDS patients, with median age 82 years (IQR 77 - 86), who were predominantly male (53.8%), non-Hispanic white (88.6%), and from urban/suburban areas (86.2%). MDS was of low, intermediate, and high histologic risk in 14.7%, 72.8%, and 12.5%, respectively, and 28.6% were transfusion dependent. Pre-existing CVD risk factors at time of MDS diagnosis were present in 12,538 patients, with baseline cardiovascular risk defined as low, intermediate, and high in 11.1%, 32.3%, and 56.6% of the cohort. The cumulative incidences of MI, ischemic stroke and composite CVD events were 11.3%, 10.6% and 20.4%, respectively. The propensity score (PS) conditional probability for being treated with HMA included demographic variables, CVD risk factors, MDS histology and transfusion dependence. Our PS model adequately predicted HMA treatment propensity (AUC 0.76). Cause-specific regression with death as competing risk, adjusted for PS and other MDS-specific treatments (ESA and lenalidomide), showed no significant effect of HMA on the risk of composite CVD events, MI, or ischemic stroke (Table 1). Conditional logistic regression in the case-crossover analysis of 1,907 patients with composite CVD events showed no significant effect of HMA. Results were similar for analysis of patients with MI and ischemic stroke (Table 2).

Conclusions:

No study has previously investigated the effect of HMA therapy on cardiovascular outcomes in patients with MDS. We demonstrate that HMA therapy is not associated with a significant risk reduction in cardiovascular events among patients with MDS patients from the SEER-Medicare database. These results show that HMA therapy is unlikely to reduce cardiovascular mortality and underscore the need for alternative therapeutic strategies targeting cardiovascular health patients with MDS.