Risk of stroke in patients with newly diagnosed multiple myeloma: a retrospective cohort study

Cerebrovascular events are a common complication among patients with cancer, increasing morbidity and mortality. However, the association between multiple myeloma and cerebrovascular events remains unclear. We therefore investigated multiple myeloma patients' risk factors for stroke to devise a better stroke-prevention strategy. This study includes consecutive patients 20 years and older who were newly diagnosed with symptomatic multiple myeloma at Taipei Veterans General Hospital, a tertiary medical center, between January 1, 2002 and December 31, 2014. The primary outcome was stroke development. Patients with head injuries, brain tumors, brain parenchymal invasions, or antecedent malignancies were excluded. Hazard ratios (HRs) of stroke risk factors for multiple myeloma patients were estimated by Cox proportional regression analysis. Overall, 395 patients with a median age of 70 years were investigated. In the median follow-up period of 18 months, cerebrovascular events occurred in 16 patients, including 10 ischemic strokes and 6 hemorrhagic strokes. The 5-year estimated cumulative incidence rate was 7.45%. In the multivariate analysis, the κ light chain isotype (adjusted HR, 8.37; 95% confidence interval [CI], 1.91-39.8), previous cerebrovascular accidents (adjusted HR, 5.16; 95% CI, 1.48-17.9), and serum creatinine > 2 mg/dL (adjusted HR, 4.21; 95% CI, 1.10-16.0) were identified as independent risk factors for stroke. Subgroup analysis showed that atrial fibrillation (adjusted HR, 8.07) and previous cerebrovascular accident (adjusted HR, 4.89) are significant risk factors for ischemic stroke. Serum creatinine > 2 mg/dL (adjusted HR, 30.6) and previous cerebrovascular accident (adjusted HR, 13.9) are significant for hemorrhagic stroke. Moreover, therapeutic strategies for multiple myeloma were not associated with stroke in our study. This study demonstrates that risk of stroke increases in myeloma patients with a κ light chain isotype, previous cerebrovascular events, and renal impairment. Further prospective clinical studies to clarify the relationship between multiple myeloma and stroke are warranted.