Study designThis is a retrospective cohort comparative study.BackgroundVitamin D supplementation is considered to be associated with good functional outcome. Thus, a few studies have proposed vitamin D supplementation is benefit to the functional outcome in LSS requiring surgery. The purpose of this study is to identify the prevalence of vitamin D deficiency in patients with LSS requiring surgery, and to compare the differences between the cases whether vitamin D is supplemented and vitamin D is not supplemented in terms of a QoL during postoperative 2 year.MethodsAll patients with LSS who underwent surgery from March 1, 2015 to August 31, 2016 were enrolled. Among them, 61 patients with vitamin D deficiency were divided into two groups (supplemented group (A) and non-supplemented group (B)). Functional outcomes using Oswestry Disability Index (ODI) and Rolland Morris Disability Index (RMDQ) and QoL using SF-36 were evaluated at 12-month and 24-month follow-up periods. Differences in functional score and SF-36 between the vitamin D supplemented and non-supplemented group were compared.ResultsAmong the total 102 patients, 78 patients (76.5%) had vitamin D deficiency. Of the 78 patients, 61 patients were included, 27 patients were group A and 27 patients were group B. There was no difference in age and 25-OHD level between the two groups (all 0 > 0.05). Group A were better functional outcomes at 2 years after surgery (p < 0.05). On the QoL, group A were higher score than group B from 12 month later after surgery (p < 0.05).ConclusionsVitamin D deficiency was highly prevalent in LSS patients (76.5%). Assessment of serum 25-hydroxyvitamin D (25(OH)D) is recommended in LSS needing surgical intervention and active treatment vitamin D supplementation and maintenance of normal range should be considered for better postoperative functional outcome and QoL.