Baseline serum 25 hydroxyvitamin D concentration does not predict functional recovery in intensive inpatient...

Vitamin D deficiency is highly prevalent among hospitalized patients, and its effects on skeletal muscle function and systemic inflammation suggest that baseline status might influence functional recovery; however, evidence specifically in intensive inpatient rehabilitation remains scarce.

In this retrospective observational cohort study, 97 adults (mean age 65.0 ± 13.1 years) admitted to intensive inpatient rehabilitation were enrolled. Serum 25-hydroxyvitamin D [25(OH)D] obtained within 48 h of admission was analyzed both as a continuous variable and categorized into deficient, insufficient, and sufficient groups. The primary outcome was the Functional Independence Measure (FIM) at discharge adjusted for admission score; secondary outcomes included the Barthel Index (BI), Functional Ambulation Category (FAC), 6-min walk test (6MWT), and length of stay. Hierarchical linear regression was performed adjusting for admission functional status, age, comorbidity burden, and diagnostic group, with robust standard errors and bootstrap confidence intervals.

Hypovitaminosis D affected 78.4% of patients. Despite substantial functional improvement across the cohort, baseline serum 25(OH)D was not associated with any outcome measure-neither as a continuous variable nor across vitamin D categories-in unadjusted or fully adjusted analyses. Admission functional status (i.e., FIM) was the dominant predictor in all models.

Baseline serum 25(OH)D did not predict functional recovery during intensive inpatient rehabilitation, irrespective of outcome measure. Although hypovitaminosis D was highly prevalent and warrants correction for skeletal health, the present study did not find evidence to support the use of serum 25(OH)D as a prognostic marker of rehabilitation outcome.