(P-271) Association Between the Multiple Myeloma Treatments and Vascular Adverse Events in Taiwanese Multiple Myeloma Patients: A Population-based Cohort Study

Background: The immunomodulatory agents have become the mainstream therapy of multiple myeloma (MM) in recent decades. Proteasome inhibitors and some monoclonal antibodies also demonstrate favorable efficacy in MM patients. Nevertherthess, concerns regarding the association between MM treatment and vascular adverse events (VAEs) has been raised.

Objectives: To investigate the incidence of VAEs in Taiwanese MM patients treated with different medications and identify potential risk factors of treatment-associated VAEs.

Methods: We conducted a retrospective cohort study using the Taiwan Cancer Registry (TCR) and National Health Insurance Research Database (NHIRD). Adult patients diagnosed with MM from 2008 to 2016 were identified from the TCR. The outcome of interest was VAEs. In the first part of our analysis, the most frequently-prescribed treatment within the first year since diagnosis of MM were surveyed and further categorized into 6 groups. In the second part of our analysis, time-varying Cox regression was adopted to analyze the hazard ratio (HR) of VAEs between different treatment combinations and to identify potential risk factors, with patients’ baseline characteristics, comorbidities, and comedications as fixed covariates and monthly MM treatment as time-varying covariates.

Results: A total of 3699 newly diagnosed MM patients treated with at least one of the immunomodulatory agents were identified (mean age: 66.4 years; male: 55.3%) and followed for a median of 1.3 years. The most frequently-prescribed treatment included thalidomide monotherapy, thalidomide/bortezomib/steroid combination, thalidomide/steroid combination, botezomib/steroid combination, and thalidomide/steroid/melphalan combination. The crude incidence rate of VAE was 3.0 per 100 person-years among all MM patients receiving treatment. The cumulative incidence of VAE was 6.3%. In the Time-varying Cox regression analysis, none of the identified treatment groups demonstrates significantly increased risk of VAEs, although an increased trend of VAEs was observed in thalidomide monotherapy. Other risk factors, including older age, male, baseline diabetes mellitus without chronic complications, prior history of VAEs, use of antiplatelet, antihemorrhagics, lipid-lowering agents, antihypertensive agents and hormone therapy, were significantly associated with increased risk of VAEs.

Conclusions: No significant association between use of MM treatment and risk of VAEs was found in our study. Other potential risk factors include older age, male, history of specific comorbidities and use of specific medications.