The Clinical Efficacy And Safety Of Vitamin D In The Treatment Of Inflammatory Bowel Disease: A Systematic Review

Background: A number of domestic and foreign studies have shown that vitamin D deficiency is associated with the occurrence and development of inflammatory bowel disease.Vitamin D may induce remission of IBD through anti-inflammation and repair of the intestinal mucosal barrier,thereby improving disease activity and quality of life.However,the effect of vitamin D supplementation on clinical outcomes in IBD remains inconclusive.Objective: This study aimed to explore the effects of vitamin D supplementation on serum 25-hydroxyvitamin D [25(OH)D] levels,clinical recurrence rate,disease activity index,and inflammatory indexes included CRP,hs-CRP,and ESR in patients with IBD through Meta-analysis,and to evaluate the clinical efficacy and safety of vitamin D in the treatment of IBD,providing evidence-based clinical treatment for this disease.Methods: The literatures about vitamin D for inflammatory bowel disease were searched by Pub Med,Embase,Web of Science,The Cochrane Library,China National Knowledge Infrastructure(CNKI),VIP Journal Integration Platform(VIP)and Wanfang database from December 2018 to December 2020,since the establishment of the database to December 31,2020.The literatures were selected according to the inclusion and exclusion criteria.Data information from the included literatures were extracted,and the data were managed as well as analyzed by Stata 16.0 software and Rev Man 5.4 software.The outcomes included serum 25(OH)D levels,disease recurrence rates,inflammatory indicators,disease activity indices and adverse events were compared between the experimental group and the control group.Results: 18 randomized controlled trial studies from 17 eligible literatures were included.Meta-analysis showed that: 1.Vitamin D supplementation increased serum25(OH)D levels(ng/m L)in patients with IBD [WMD=15.11,95% CI(10.52,19.70),P<0.001].2.Vitamin D supplementation reduced the recurrence rate of IBD [RR=0.33,95% CI(0.17,0.65),P=0.001<0.05].3.Vitamin D supplementation reduced the levels of some inflammatory indicators in IBD [hs-CRP(mg/L): WMD=-1.58,95% CI(-2.95,-0.21),P=0.024<0.05;CRP(mg/L): WMD=-1.48,95% CI(-1.77,-1.19),P<0.001].However,there was no significant reduction in ESR [ESR(mm/h): WMD=-0.23,95%CI(-5.75,5.29),P=0.935>0.05].4.Vitamin D supplementation had no significant effect on CDAI scores of CD patients [WMD=9.51,95% CI(-4.49,23.51),P=0.183> 0.05].5.Vitamin D for IBD did not significantly increase adverse effects [RR=0.44,95% CI(0.17,1.10),P=0.078>0.05].6.The results of subgroup analysis showed that(1)Compared to the treatment with lower doses of vitamin D [WMD=4.35,95%CI(-4.31,13.01),P=0.325>0.05],high doses of vitamin D for IBD could more significantly elevated serum 25(OH)D levels [WMD = 25.67,95% CI(14.99,36.34),P < 0.001].(2)Compared with the control group,the recurrence rate of the experimental group was lower in the study with a course of 1 year [RR=0.36,95% CI(0.17,0.80),P=0.012<0.05],while there was no statistical difference between the experimental group and the control group in the study with a course of 26 weeks and 3 months[26-week: RR=0.32,95% CI(0.04,2.18),P=0.302 > 0.05;3-month: RR=0.26,95% CI(0.06,1.16),P=0.078 > 0.05].Conclusion: Vitamin D supplementation in patients with IBD can effectively correct low serum vitamin D levels,control the recurrence rate of the disease and reduce some inflammatory indicators without obvious adverse effects.Therefore,vitamin D is recommended for the adjuvant treatment of IBD.Higher doses of vitamin D are recommended for supplemental therapy as long as patients are tolerated.