Coronary Heart Disease Risk in Blood or Marrow Transplant Survivors

INTRODUCTION: Exposure to total body irradiation (TBI) increases the risk for cardiovascular risk factors (CVRFs) such as diabetes, hypertension and dyslipidemia in Blood or Marrow Transplant (BMT) survivors with the potential to increase the risk of post-BMT Coronary Heart Disease (CHD). Chest radiation is associated with accelerated atherosclerosis in conventionally treated patients. These factors, with or without additional factors such as smoking likely place BMT survivors at a high risk for CHD. Yet, a comprehensive evaluation of the risk of late-occurring CHD in BMT survivors is lacking. We addressed this gap using the resources offered by the BMT survivor study (BMTSS).

METHODS: BMTSS includes patients transplanted between 1974 and 2014 at 3 US sites, and who had survived ≥2 years after BMT, and were alive and ≥18 years at BMTSS survey completion. The BMTSS survey asked participants to report chronic health conditions diagnosed by their healthcare provider (including CHD, diabetes, hypertension and dyslipidemia), along with age at diagnosis. The participants self-reported sociodemographics and health behaviors. Information regarding primary cancer diagnosis, therapeutic exposures, donor type, stem cell source, and history of chronic graft vs. host disease (GvHD; for allogeneic BMT recipients) was abstracted from medical records. A cohort of 1,131 siblings completed the BMTSS survey and served as a comparison group. We obtained informed consent from all participants.

RESULTS: The study included 3,479 BMT survivors; 50.3% had received an allogeneic BMT, 54.8% were males, and 71.4% were non-Hispanic whites. Median age at study participation was 59 years (interquartile range [IQR]: 48-66 years) for BMT survivors and 57 years (IQR: 46-64 years) for siblings. BMT survivors were followed for a median of 9 years (range: 2-41 years) from BMT. CHD developed after BMT in 122 BMT survivors (52 allogeneic, 70 autologous).

BMT recipients compared with siblings: After adjusting for sociodemographics and comorbidities, allogeneic BMT survivors were at a 7.2-fold higher odds (95%CI: 4.0-13.0, p<0.0001) and autologous BMT recipients at a 11.7-fold higher odds (95%CI: 6.8-20.2, p<0.0001) of reporting CHD as compared to siblings.

Allogeneic BMT survivors: The 20 year cumulative incidence of CHD was 4.7% for allogeneic BMT recipients. Increasing age at BMT (HR=1.05/year, 95%CI: 1.02-1.07, p<0.0001), male sex (HR=2.09, 95%CI: 1.14-3.82, p=0.017), history of CVRFs (HR=3.6, 95%CI: 1.72-7.41, p=0.0006), and pre-BMT targeted chemotherapy such as tyrosine kinase inhibitors (HR=2.7, 95%CI: 1.10-6.77, p=0.030) were associated with increased CHD risk. The 20 year cumulative incidence of CHD among patients with CVRFs was 6.6% vs. 1.9% (p=0.005) among those who did not have CVRFs (Fig 1).

Autologous BMT survivors: The 20 year cumulative incidence of CHD was 9.1% for autologous BMT recipients. The risk factors for CHD in autologous BMT survivors included: increasing age at BMT (HR=1.06/year, 95%CI: 1.03-1.09, p<0.0001), male sex (HR=2.3, 95%CI: 1.30-3.90, p=0.004), history of smoking (HR=1.66, 95%CI: 1.03-2.67, p=0.038), CVRFs (HR=1.77, 95%CI: 1.04-3.01, p=0.036), arrhythmia (HR=1.85, 95%CI: 1.01-3.42, p=0.048) and history of pre-BMT chest radiation (HR=4.56, 95%CI: 2.1-9.88, p=0.0001). For every 1 Gray increase in the dose of chest radiation, there was a 4% increase in the risk of CHD, p=0.0002. The 20 year cumulative incidence of CHD among patients with CVRFs was 10.2% vs. 7.4% among those who did not have CVRFs (p=0.04) (Fig 2).

CONCLUSION: BMT survivors are at a 7-fold to 12-fold higher risk of CHD compared with a sibling comparison group. CVRFs are independent risk factors for CHD both among allogeneic and autologous BMT recipients. Pre-BMT chest radiation further increases this risk in autologous BMT recipients. These findings suggest a need for aggressive management of CVRFs in BMT recipients to prevent CHD-related morbidity.