Prevalence and associated factors of vitamin D deficiency after Roux-en-Y gastric bypass: a systematic review and meta-analysis.

OBJECTS: To estimate the prevalence and associated factors of vitamin D deficiency (VDD) after Roux-en-Y gastric bypass (RYGB). METHODS: PubMed, EMBASE, and CENTRAL were searched for relevant records from inception to 17 March 2023, using search terms: vitamin D, vitamin D3, vitamin D deficiency, hypovitaminosis D, gastric bypass, and RYGB. Studies were eligible for inclusion if they provided related data on VDD prevalence after RYGB. RESULTS: Of the 1119 screened studies, 72 studies involving 7688 individuals were enrolled in the final analysis. The prevalence estimates of VDD after RYGB were 42%. Subgroup analyses suggested the pooled prevalence of postoperative VDD was 35% for follow-up duration less than or equal to 1 year, 43% for greater than 1 and less than or equal to 5 years, and 54% for greater than 5 years. Meta-regression showed that VDD prevalence was positively correlated with follow-up time. Also, the prevalence was higher in studies with inadequate vitamin D supplementation than in those with adequate supplementation and in Asia population than in those from South America, Europe, and North America. Other factors associated with high VDD prevalence after RYGB included high presurgical VDD prevalence, noncompliant patients, and black populations. No significant association existed between VDD and alimentary length. CONCLUSION: VDD presented a high prevalence in patients following RYGB. It occurred more frequently with longer postoperative follow-up time. Population-specific vitamin D supplementation measures, targeted treatment for presurgical VDD, improved patient compliance, and periodical follow-ups were necessary to reduce VDD and other adverse outcomes.

Prevalence and associated factors of secondary hyperparathyroidism after Roux-en-Y gastric bypass: A meta-analysis.

This study aimed to investigate the prevalence and factors associated with secondary hyperparathyroidism (SHPT) after Roux-en-Y gastric bypass (RYGB). We searched PubMed, EMBASE, and CENTRAL for relevant studies using search terms gastric bypass, RYGB and hyperparathyroidism. Thirty-four cohort studies with 4331 patients were incorporated into the final meta-analysis. Overall estimates of the prevalence of SHPT following RYGB were 39%. Subgroup analyses indicated the pooled prevalences of SHPT were 25%, 42%, 48%, and 54% for ≤1 year, >1 and ≤5 years, >5 and ≤10 years, and >10 years, respectively, after RYGB. Meta-regression showed that SHPT occurred was positively related to follow-up durations (p = 0.001). Additionally, SHPT prevalence was higher in studies in which calcium and vitamin D supplementation were considered inadequate than in those which were adequate (p = 0.002). SHPT is highly prevalent in individuals with obesity after RYGB. It seems to progress with time after surgery. Routine calcium and vitamin D supplementation post-RYGB together with targeted treatment of vitamin D deficiency, reasonable adjustment of the doses of supplementation with regular follow-up, and improved patient compliance, as well as long-term screening, are necessary to prevent the development of SHPT.

Nutritional Deficiencies in Chinese Patients Undergoing Gastric Bypass and Sleeve Gastrectomy: Prevalence and Predictors.

BACKGROUND: Nutritional deficiencies have been reported in bariatric surgery patients with inconsistent results. However, scarce data exist for Chinese patients. We aimed to assess nutritional deficiencies in Chinese patients undergoing Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), and to identify predictors of postoperative nutritional status. METHODS: A retrospective review of a prospectively collected database was conducted in the patients undergoing RYGB and SG in our hospital between June 2013 and January 2017. Anthropometric data and nutritional data were collected before surgery, at 6 and 12 months postoperatively. RESULTS: This study enrolled 269 patients (120 RYGB, 149 SG). Nutritional deficiencies were common in Chinese bariatric candidates, with vitamin D deficiency the most serious (78.8%), followed by vitamin B1 (39.2%), vitamin B6 (28.0%), folate (26.8%), vitamin C (18.0%) albumin (13.4%), transferrin (11.6%), and phosphorus (11.5%). Despite postoperative routine multivitamin and calcium supplements, nutritional deficiencies were still obvious for RYGB and SG patients. The prevalence of hemoglobin and vitamin B12 deficiencies increased remarkably in the RYGB group; the levels of hemoglobin, globin, vitamin B12, and ferritin decreased significantly (P < 0.05). Preoperative hemoglobin, vitamin B12, and ferritin levels were independently associated with postoperative decrease, respectively. Deficiencies of vitamin D, vitamin B1, vitamin B6, vitamin C, and albumin before surgery were predictors for deficiencies 1 year after surgery, respectively. CONCLUSION: Nutritional deficiencies are common in Chinese bariatric surgery candidates. Similar deficiencies were also seen after RYGB and SG. Routine evaluation and related corrections of preoperative nutritional abnormity could contribute to postoperative nutrient balance.