Hypovitaminosis D in acute inpatient cancer rehabilitation: Prevalence, predictors, and practical implications

Abstract Background Hypovitaminosis D is associated with adverse health outcomes, including increased mortality in patients with cancer. Although vitamin D insufficiency (23%–72%) and deficiency (20%–71%) are common among patients admitted to inpatient rehabilitation, their prevalence and predictors in cancer‐specific inpatient rehabilitation populations remain uncharacterized. Objective To determine the prevalence of hypovitaminosis D in adults with cancer admitted to acute inpatient rehabilitation and to identify demographic, clinical, laboratory, and functional predictors. Design Retrospective observational cohort study. Setting An inpatient rehabilitation service within a tertiary cancer hospital. Patients Consecutive adults with a cancer diagnosis admitted for acute inpatient rehabilitation between December 1, 2023, and May 24, 2024. Interventions Not applicable. Main Outcome Measure(s) The primary outcome was the prevalence of hypovitaminosis D (25‐hydroxyvitamin D ≤ 29 ng/mL). Secondary outcomes included predictors of hypovitaminosis D and evaluation of the timing and frequency of vitamin D supplementation upon index hospital admission, upon admission to inpatient rehabilitation, and at 3 and 6 months post discharge. Results Of 126 patients, 78 (62%) had hypovitaminosis D. Significant predictors included relatively younger age (median 66.0 vs 71.5 years; effect size, 5.5 with 95% confidence interval CI, 1.60–9.40, p = .006) and presence of neurogenic bladder or bowel (16.7% vs 2.4%; odds ratio, 0.12 with 95% CI, 0.003–0.924, p = .019). At hospital admission, 29% ( n = 36) were receiving supplementation, and 40% ( n = 51) initiated supplementation during inpatient rehabilitation. At 3 and 6 months post discharge, 48% ( n = 61) and 39% ( n = 49), respectively, had records of continued supplementation. Vitamin D supplementation was generally well tolerated during inpatient rehabilitation, with only minor side effects that were managed in three patients. Conclusions Hypovitaminosis D was highly prevalent among adult patients with cancer undergoing inpatient rehabilitation. Identified predictors, including relatively younger age and neurogenic bladder or bowel, may help guide targeted screening.