Association of anemia with cardiovascular and cancer mortality among stroke survivors: A cohort study (NHANES 1999–2018)

A substantial proportion of stroke survivors have comorbid anemia, which has been associated with poor stroke outcomes. While previous studies have linked anemia to increased all-cause mortality among stroke survivors, limited research has focused on its association with cause-specific mortality. This study investigates the relationship between anemia and cause-specific mortality in stroke survivors. A total of 1561 stroke survivors were included from the NHANES 1999 to 2018 database. Restricted cubic spline (RCS) analysis was used to examine the association between hemoglobin (HGB) levels and all-cause mortality. Propensity score matching was performed at a 1:2 ratio to balance baseline characteristics. The relationships between anemia and cardiovascular, cancer-related, and other-cause mortality were assessed using competing risks models and cumulative incidence function (CIF) curves. RCS analysis revealed an L-shaped association between HGB and all-cause mortality, with a sharp increase in mortality risk below approximately 14 g/dL. In the competing risks model, anemia was significantly associated with an increased risk of cardiovascular mortality (subdistribution hazard ratio [sHR], 1.40; 95% CI: 1.02-1.90; P = .03), but was not significantly associated with cancer or other-cause mortality. CIF curves showed that the difference in cardiovascular mortality risk between anemic and non-anemic groups was more pronounced before 150 months of follow-up, with the difference narrowing after 200 months. Anemia is associated with an increased risk of cardiovascular mortality among stroke survivors.