Venous Thromboembolism is Associated With Lack of Vitamin D Supplementation in Patients With Spinal Cord Injury and Low Vitamin D Levels

Background: The role of vitamin D in the pathogenesis of venous thromboembolism (VTE) and prevalence of low vitamin D (LVitD) in spinal cord injury (SCI) has motivated vitamin D testing and supplementation. This is an exploratory study of data collected at a time before the routine clinical practice of vitamin D supplementation, allowing for evaluation of the natural history of vitamin D levels in patients with SCI.

Objective: To determine if vitamin D supplementation in persons with SCI and LVitD levels is associated with decreased prevalence of VTE.

Design: Retrospective cohort study.

Setting: Rehabilitation Center at a Level I Trauma Center.

Participants: Patients with SCI admitted to acute inpatient rehabilitation (N = 282).

Main Outcome Measures: VTE prevalence in patients with LVitD levels, grouped by presence or absence of vitamin D supplementation.

Results: Of the acute inpatient SCI population, 80% (227/282) of patients demonstrated vitamin D levels <30 ng/mL (LVitD). Although the incidence of VTE was almost double in the LVitD group, 19% (43/227) of the patients in the LVitD group had VTE versus 9% (5/55) of patients with vitamin D levels ≥30 ng/mL (normal VitD [NVitD]); this difference was not statistically significant (P = .108, Cramer's V = .104). When the role of vitamin D supplementation was analyzed, individuals in the LVitD group who received no vitamin D supplementation (LVitDSuppNegative) had a higher incidence of VTE (statistically significant) compared to the LVitD group with vitamin D supplementation (LVitDSuppPositive) (24% [42/178] vs. 2% [1/49]) (P < .001, Cramer's V = .226). In post hoc exploratory analyses, the VTE rate of patients in the LVitDSuppNegative group was noted to be significantly higher than that in all other patient groups combined (P < .001, Cramer's V = .229). A binary logistic regression model incorporating clinical covariates also showed this grouping to be significant.

Conclusion: A significant association appears to exist between lack of vitamin D supplementation and VTE occurrence in persons with acute SCI and LVitD levels.

Level Of Evidence: III.