Anemia as a predictive factor for brain metastases: A propensity score matched retrospective cohort study.

e14014 Background: Renal cell carcinoma, lung carcinoma, breast carcinoma, and melanoma are cancers that commonly metastasize to the brain. Currently, it is unknown what makes a person more likely to develop brain metastases. Anemia might be linked with tumor hypoxia, which induces angiogenesis and increases tumor aggressiveness. However, it is unclear how anemia might affect the risk of brain metastases in these patients. Methods: We utilized the 2024 TriNetX database in conducting this retrospective cohort study. We identified patients with anemia since 2010 using appropriate ICD-10 diagnostic codes. We stratified patients into two cohorts based on the degree of their hemoglobin level: cohort 1 consisted of patients with a hemoglobin of 7-9.9 gm/dL, while cohort 2 consisted of patients with a hemoglobin of 10-13 gm/dL. Kaplan-Meier Analysis with log-rank test was used to calculate hazard ratios (HRs) for brain metastases and other secondary outcomes. A p-value < 0.05 was considered statistically significant. Results: Each cohort consisted of 57,134 patients after propensity score matching with similar baseline characteristics. Average age at the time of index was 66 years in both groups, and 47% of each cohort was female. In cohort 1, the ethnicity distribution was 59% White, 6% Hispanic, and 18% African American. In cohort 2, the ethnicity distribution was 60% White, 6% Hispanic, and 18% African American. Upon analysis, our study found that, within the last 25 years, patients with a lower hemoglobin level had significantly higher risk of brain metastases (HR 1.62, 95% CI: 1.55–1.69, p < 0.0001). These same patients also had a higher risk for stroke (HR 1.44, 95% CI: 1.37–1.51, p < 0.0001), seizure (HR 1.53, 95% CI: 1.45–1.61, p < 0.0001), intracerebral hemorrhage (HR 1.61, 95% CI: 1.45–1.78, p < 0.0001), hospitalizations (HR 2.24, 95% CI: 2.20–2.28, p < 0.0001), and all-cause mortality (HR 2.92, 95% CI: 2.86–2.98, p < 0.0001). Conclusions: Our study found that patients with lower hemoglobin levels have an increased risk of brain metastases, stroke, seizure, intracerebral hemorrhage, hospitalizations, and all-cause mortality. Further longitudinal studies are needed to explore the relationship between anemia and brain metastases.