Effect of vitamin D supplementation on skeletal muscle function and quality of life in patients with chronic intestinal failure: a randomized controlled trial

Vitamin D deficiency is common in patients with chronic intestinal failure (CIF); however, the effectiveness of high-dose vitamin D supplementation remains unclear. This study aimed to investigate the effects of high-dose vitamin D supplementation on skeletal muscle mass, function, and quality of life (QoL) in patients with CIF. This was a single-center, prospective, randomized, double-blind, placebo-controlled trial conducted at a tertiary hospital in China. Participants included individuals aged 18–70 years with chronic intestinal failure and vitamin D deficiency (serum 25(OH)D < 30 ng/ml). Eighty-four adult patients were randomly assigned (1:1) to either the vitamin D group (intramuscular injection of 600,000 units of vitamin D2 every two weeks for 10 weeks) or the control group (matched placebo). The primary outcomes were appendicular skeletal muscle mass index (assessed by bioelectrical impedance), handgrip strength, 6-meter walking speed, and quality of life (SF-36 scales) from the date of randomization to the end of the 12-week follow-up period. The analysis was performed on an intention-to-treat principle. Eighty-four patients were randomized to the control group (n = 42; mean age, 52.8 ± 15.6 years) or the vitamin D group (n = 42; mean age, 52.9 ± 16.2 years). At the 12-week follow-up, serum 25-hydroxyvitamin D levels were significantly higher in the vitamin D group than in the control group (96.7 ± 5.8 vs. 23.8 ± 4.1 ng/mL; p < 0.001). Compared with the control group, the vitamin D group showed clinically meaningful improvements in the appendicular skeletal muscle mass index, handgrip strength, 6-meter walking speed, and the SF-36 physical component summary score (all p < 0.05 after Bonferroni correction). No other clinically significant differences were observed between the groups in the remaining secondary clinical and safety endpoints. High-dose intramuscular vitamin D2 supplementation for 10 weeks was significantly associated with improved skeletal muscle mass, function, and QoL in patients with CIF. ClinicalTrials.Gov Identifier: NCT06283615. Registered 11 March 2024, https://clinicaltrials.gov/study/NCT06283615. High-dose intramuscular vitamin D2 supplementation was associated with significant improvements in skeletal muscle mass, function, and QoL in patients with chronic intestinal failure. The 10-week high-dose vitamin D2 treatment demonstrates rapid, safe, and effective correction of serum vitamin D deficiency in patients with chronic intestinal failure. This randomized controlled trial provides high-quality evidence supporting the administration of high-dose vitamin D2 supplementation in patients with chronic intestinal failure.