Serum vitamin d levels predict hospital-free days in outpatient allogeneic stem cell transplantation survivors: implications for long-term health outcomes.

PURPOSE: Optimizing long-term health outcomes and minimizing healthcare utilization are crucial for outpatient allogeneic hematopoietic stem cell transplantation (allo-HSCT) survivors. Hospital-free days (HFDs) serve as patient-centered indicators of healthcare burden and physical stability. Although vitamin D (25(OH)D) has immunomodulatory effects, its relationship with HFDs in survivors in remission remains unclear. We investigated the predictive value of serum 25(OH)D levels for HFDs and hospitalization-free survival (HFS).

METHODS

This prospective single-center study enrolled 51 adult allo-HSCT survivors in complete remission who visited outpatient clinics. Serum 25(OH)D levels were measured. The primary outcome was HFDs (days alive and out-of-hospital) over 3 years, categorized into four ordered groups. The secondary outcome was HFS (time to death, relapse, or hospitalization). Multivariable ordinal logistic (HFDs) and Cox proportional hazards (HFS) regression analyses were performed, adjusting for confounders using stepwise selection.

RESULTS

The median patient age was 67.7 years. In multivariable analysis, higher serum 25(OH)D levels significantly predicted better HFD outcomes (adjusted odds ratio = 1.13 per ng/mL; 95% CI = 1.04-1.24; p = 0.001). Higher 25(OH)D levels also independently predicted improved HFS (adjusted hazard ratio = 0.89 per ng/mL; 95% CI = 0.82-0.95; p = 0.001). The Kaplan-Meier analysis confirmed better HFS in patients with 25(OH)D levels above the median (log-rank p = 0.029). Chronic graft-versus-host disease and time since SCT were associated with 25(OH)D levels.

CONCLUSION

In outpatient allo-HSCT survivors, higher serum 25(OH)D levels independently predicted HFDs, suggesting reduced healthcare burden and improved HFS. Vitamin D status warrants further investigation as a potential modifiable target for enhancing long-term HSCT outcomes.