Osteomalacia after Roux-en-Y gastric bypass

Oral vitamin D supplementation for adults with obesity undergoing bariatric surgery

BACKGROUND

Vitamin D deficiency following bariatric surgery is common and is expected to be associated with a deleterious impact on the skeleton. However, the benefits of vitamin D supplementation and the optimal dose in this population is currently unknown. The available guidelines on the topic are derived from experts' opinions, and are not evidence based.

OBJECTIVES

To compare the effects of different doses of vitamin D supplementation (low dose (less than 600 international units (IU)/day), moderate dose (600 IU/day to 3500 IU/day), high dose (greater than 3500 IU/day)) to each other or to placebo in adults living with obesity undergoing bariatric surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, two trial registries, and the reference lists of systematic reviews, articles, and health technology assessment reports without language restrictions. The last search of all databases was 27 June 2023, except Embase, which we searched on 14 August 2015.

SELECTION CRITERIA

We included randomised controlled trials or controlled clinical trials on vitamin D supplementation comparing different doses or comparing vitamin D to placebo in people undergoing bariatric surgery.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were fractures and adverse events. Secondary outcomes were vitamin D status, all-cause mortality, bone mineral change, secondary hyperparathyroidism, health-related quality of life, and muscle strength. We used GRADE to assess the certainty of the evidence for each outcome in each comparison.

MAIN RESULTS

We identified five trials with 314 participants. We included three trials in the quantitative analysis. Moderate-dose vitamin D compared to placebo One trial compared moderate-dose vitamin D (3200 IU/day) to placebo. Moderate-dose vitamin D, compared to placebo, may improve vitamin D status and may result in little to no difference in the achieved parathyroid hormone level (achieved 25-hydroxyvitamin D level: mean difference (MD) 13.60 ng/mL, 95% confidence interval (CI) 7.94 to 19.26; achieved parathyroid hormone level: -6.60 pg/mL, 95% CI -17.12 to 3.92; 1 study, 79 participants; low-certainty evidence). The trial reported no adverse events in the moderate-dose vitamin D arm, but did not provide any information on adverse events in the placebo arm. There were no data on fractures, all-cause mortality, bone density change, health-related quality of life, and muscle strength. High-dose vitamin D compared to moderate-dose vitamin D Two trials in Roux-en-Y gastric bypass compared moderate-dose (equivalent dose 800 IU/day to 2000 IU/day) to high-dose (equivalent dose 5000 IU/day to 7943 IU/day) vitamin D. The evidence of high-dose vitamin D on adverse events is very uncertain (risk ratio (RR) 5.18, 95% CI 0.23 to 116.56; 2 studies, 81 participants; very low-certainty evidence). High-dose vitamin D may increase 25-hydroxyvitamin D levels compared to a moderate dose at 12 months, but the evidence is very uncertain (MD 15.55 ng/mL, 95% CI 3.50 to 27.61; I2 = 62%; 2 studies, 73 participants; very low-certainty evidence). High-dose vitamin D may have little to no effect on parathyroid hormone levels compared to a moderate dose at 12 months, but the evidence is very uncertain (MD 2.15 pg/mL, 95% CI -21.31 to 17.01; I2 = 0%; 2 studies, 72 participants; very low-certainty evidence). High-dose vitamin D may have little to no effect on mortality and bone mineral density at the lumbar spine, hip, and forearm, but the evidence is very uncertain. There were no data on fractures, health-related quality of life, or muscle strength.

AUTHORS' CONCLUSIONS

No trials reported on fractures and the evidence available on adverse events is scarce. Moderate-dose vitamin D may improve vitamin D status and may result in little to no improvement in parathyroid hormone levels compared with placebo. High-dose vitamin D supplementation (greater than 3500 IU/day) may increase 25-hydroxyvitamin D levels, and may have little to no effect on parathyroid hormone levels, compared to a moderate dose, but the evidence for both is very uncertain. The currently available limited evidence may not have a significant impact on practice. Further studies are needed to explore the impact of vitamin D supplementation on fractures, adverse events, and musculoskeletal parameters in people undergoing bariatric surgery.

Surgical Intervention Could Relieve Obstruction-Related Symptoms of Refractory Superior Mesenteric Artery Syndrome: Long-Term Follow-up Results

PURPOSE

Superior mesenteric artery syndrome (SMAS) is one of the rare causes of chronic duodenal obstruction. The aim of our study was to evaluate the outcomes of surgical management of refractory SMAS (Re-SMAS) in our institution during the last decade.

MATERIALS AND METHODS

Consecutive patients diagnosed as Re-SMAS and underwent surgical intervention were retrospectively enrolled. A modified Likert-scale-based questionnaire was used to quantify the symptoms of SMAS. The primary outcome was the increase of BMI and symptomatic relief after surgery.

RESULTS

From January 2010 to January 2020, 22 patients diagnosed with Re-SMAS and underwent surgery were included. Age distribution of included patients were < 19 (10/22, 45%), 19-45 (11/22, 50%), and > 45 (1/22, 5%). A significant BMI increase was recorded, [16.1 (14.6-23.7) kg/m² vs 21.9 (15.6-29.5) kg/m² before and after surgery, respectively, p < 0.001]. Up to 20 patients (20/22, 91%) reported symptomatic relief. The obstruction-related symptom score decreasing significantly (p < 0.001), with reported nausea, vomiting, and regurgitation incidences dropping from 77 to 41% (p = 0.031), 68 to 23% (p = 0.006), and 32 to 5% (p = 0.046), respectively.

CONCLUSION

Surgical interventions could relieve obstruction-related symptoms of Re-SMAS and promote weight gain. For patients who suffered from Re-SMAS and referred to surgeons mainly for obstruction-related symptoms, surgical intervention is recommended.

Bone Response to Weight Loss Following Bariatric Surgery

Obesity is a global health challenge that warrants effective treatments to avoid its multiple comorbidities. Bariatric surgery, a cornerstone treatment to control bodyweight excess and relieve the health-related burdens of obesity, can promote accelerated bone loss and affect skeletal strength, particularly after malabsorptive and mixed surgical procedures, and probably after restrictive surgeries. The increase in bone resorption markers occurs early and persist for up to 12 months or longer after bariatric surgery, while bone formation markers increase but to a lesser extent, suggesting a potential uncoupling process between resorption and formation. The skeletal response to bariatric surgery, as investigated by dual-energy X-ray absorptiometry (DXA), has shown significant loss in bone mineral density (BMD) at the hip with less consistent results for the lumbar spine. Supporting DXA studies, analyses by high-resolution peripheral quantitative computed tomography (HR-pQCT) showed lower cortical density and thickness, higher cortical porosity, and lower trabecular density and number for up to 5 years after bariatric surgery. These alterations translate into an increased risk of fall injury, which contributes to increase the fracture risk in patients who have been subjected to bariatric surgery procedures. As bone deterioration continues for years following bariatric surgery, the fracture risk does not seem to be dependent on acute weight loss but, rather, is a chronic condition with an increasing impact over time. Among the post-bariatric surgery mechanisms that have been claimed to act globally on bone health, there is evidence that micro- and macro-nutrient malabsorptive factors, mechanical unloading and changes in molecules partaking in the crosstalk between adipose tissue, bone and muscle may play a determining role. Given these circumstances, it is conceivable that bone health should be adequately investigated in candidates to bariatric surgery through bone-specific work-up and dedicated postsurgical follow-up. Specific protocols of nutrients supplementation, motor activity, structured rehabilitative programs and, when needed, targeted therapeutic strategies should be deemed as an integral part of post-bariatric surgery clinical support.

A Case Report of Severe Osteomalacia in a Young Patient After Bariatric Surgery

Obesity can promote several metabolic, cardiovascular, and musculoskeletal complications and has been associated with poor quality of life. The treatment of obesity can range from simple lifestyle modifications or medications to complicated bariatric surgeries. Although bariatric surgery has been a proven treatment for morbid obesity, it has also been associated with multiple consequences and complications. Several reports and studies have revealed bone loss or decreased bone mineral density (BMD), fractures, or even several metabolic bone diseases, such as osteoporosis, following bariatric surgery. This case report aims to increase awareness on postoperative patient supplementation compliance and incorporation of early detection and intervention. This case report involves a 39-year-old male who underwent laparoscopic biliopancreatic diversion 10 years prior to presentation. The patient was not compliant with his supplements for over nine years, which lead to multiple fragility fractures, myopathy, and muscle atrophy due to hypocalcemia, vitamin D deficiency, hyperparathyroidism, and other electrolyte disturbances. He has since been treated with supplements and physiotherapy for 10 months and showed clinical improvement. This case report highlights the importance of pre- and postoperative screening of bone loss risks and any vitamin or mineral deficiencies with subsequent correction via supplements. Moreover, it emphasizes the need for more studies on the complications of late post-bariatric surgeries.

Bisphosphonate-Induced Deterioration of Osteomalacia in Undiagnosed Adult Fanconi Syndrome

We describe two women with a misdiagnosed fracturing bone disease who were treated erroneously with i.v. zoledronate. Over the next year, they suffered marked clinical and radiographic deterioration in skeletal disease. Both were eventually diagnosed with hypophosphatemic osteomalacia secondary to acquired Fanconi syndrome (caused by light-chain myeloma in one case and tenofovir treatment in the other). Appropriate treatment with phosphate supplementation was instituted with clinical improvement. These cases illustrate the importance of not missing osteomalacia in adults presenting with fractures, and the potentially damaging effects of treatment with long-acting inhibitors of bone resorption in these circumstances. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Russian national clinical recommendations for morbid obesity treatment in adults. 3rd revision (Morbid obesity treatment in adults)

The presented paper is a third revision of the clinical recommendations for the treatment of morbid obesity in adults. Morbid obesity is a condition with body mass index (BMI) 40 kg / m2 or a BMI 35 kg / m2 in the presence of serious complications associated with obesity. The recommendations provide data on the prevalence of obesity, its etiology and pathogenesis, as well as on associated complications. The necessary methods for laboratory and instrumental diagnosis of obesity are described in detail. In this revision of the recommendations, the staging of prescribing conservative and surgical methods for the treatment of obesity are determined. For the first time, a group of patients with obesity and type 2 diabetes mellitus is selected, in whom metabolic surgery allows a long-term improvement in the control of glycemia or remission of diabetes mellitus.

The Effect of a Muscle Weight-Bearing and Aerobic Exercise Program on the Body Composition, Muscular Strength, Biochemical Markers, and Bone Mass of Obese Patients Who Have Undergone Gastric Bypass Surgery

BACKGROUND

The effect of an exercise program on the body composition, muscular strength (MS), biochemical markers, and bone mineral density (BMD) of individuals undergoing gastric bypass is unclear. We assessed lean mass (LM), MS, bone remodeling markers, and BMD before and after supervised weight-bearing and aerobic exercise training in obese patients who underwent Roux-en-Y gastric bypass (RYGB).

METHODS

This study included 37 obese patients (81.1% women, mean age 38.2 years, mean body mass index 42.4 ± 0.5 kg/m²). Whole body densitometry was used to evaluate pre- and postoperative BMD, total body fat, and LM. Serum calcium, parathyroid hormone, 25-hydroxyvitamin D, and bone remodeling markers were measured. MS was determined through the concentric 10 repetition maximum test. Postoperatively, participants were divided into two groups: the training group, who followed an exercise program (TG, n = 18), and the control group, who did not (CG, n = 19).

RESULTS

After 1 year, the TG showed a lower decrease in total BMD and at the lumbar spine and right hip compared with the CG (p < 0.001). The TG had lower mass reduction and an increase in upper limb LM compared with the CG (both p < 0.05). There was no significant difference between groups in bone markers or calcium metabolism. MS was higher in the TG than the CG (p < 0.05).

CONCLUSION

The supervised exercise program attenuated lumbar spine and right hip BMD loss and improved LM in the arms and overall MS but did not affect bone remodeling.

Hypocalcemia and osteomalacia after bariatric surgery

INTRODUCTION

Obesity has become a major health problem not only in industrialized societies but also in developing countries. Multiple studies have shown that bariatric surgery has been effective in reducing substantial amount of weight and also the comorbidities and is being performed more frequently as an established treatment. Due to anatomical and physiological alterations after surgery that impairs absorption of vitamin D and calcium, two fundamental factors in bone formation, their intestinal absorption is highly compromised.

CASE REPORT

We present a 48-year-old woman who was visited in emergency room for generalized bone pain, perioral paresthesia and carpopedal spasm. She had undergone bariatric surgery 15 years ago. Chvostek's sign and Trousseau's sign were positive. Examination of thoracic ribs elicited severe pain on palpation. Laboratory evaluation revealed: Ca = 6.1 mg/dL, P= 2.1 mg/dL, alkaline phosphatase = 432 (160-303), PTH=541 pg/mL, and 25(OH)D3= 3 ng/mL. Whole body bone scan showed increased uptake in the anterior arc of left 6th rib, posterior arc of left 6th and 12th ribs with increased uptake of costochondral joints.

CONCLUSION

Our case highlights the possible consequences that bariatric surgery may have on bone and mineral health and the need for regular and proactive follow-up of the patients.

Changes in Bone Metabolism in Morbidly Obese Patients After Bariatric Surgery: A Meta-Analysis

BACKGROUND

The aim is to evaluate via meta-analysis bone metabolism and bone mineral density (BMD) in morbidly obese patients before and after bariatric surgery.

METHODS

We searched Medline, EMBASE, and the Cochrane Library for relevant studies published before January 2014. The following outcomes were evaluated: serum calcium, serum parathyroid hormone (PTH), serum 25-hydroxyvitamin D [25(OH)D], serum or urinary N-telopeptide (NTX), bone-specific alkaline phosphatase (BSAP), and bone mineral density (BMD).

RESULTS

Ten studies, including 344 patients, met our inclusion criteria. Results showed a significant decrease in serum calcium (MD = -0.10, 95 %CI -0.14 to -0.07, P < 0.00001) and increase in serum PTH (MD = 12.41, 95 %CI 6.51 to 18.31, P < 0.00001) but no significant difference in serum 25(OH)D (MD = 1.35, 95 %CI -1.12 to 3.83, P = 0.28) following bariatric surgery. There were significant increases in serum or urinary NTX (MD = 18.49, 95 %CI 3.33 to 33.66, P = 0.02) and BSAP (MD = 7.47, 95 %CI 0.21 to 14.72, P = 0.04) but a significant decrease in BMD (MD = -0.08, 95 %CI -0.13 to -0.04, P < 0.00001) after bariatric surgery.

CONCLUSION

BMD was significantly decreased, while bone turnover was elevated, and bone remodeling was accelerated following bariatric surgery. Basal bone metabolism should be evaluated preoperatively. To prevent secondary hyperparathyroidism and bone loss, calcium and vitamin D should be monitored closely and supplemented accordingly after the surgery.

Reconstruction method as an independent risk factor for the postoperative decrease in hemoglobin in stage I gastric cancer

BACKGROUND AND AIM

No study has compared the incidence of postoperative anemia between two reconstruction methods, Billroth-I (B-I) and Roux-en-Y (R-Y) reconstructions, after distal gastrectomy for gastric cancer (GC). In this study, we wished to examine the postoperative decrease in hemoglobin (Hb) as an indicator of iron-deficiency anemia.

METHODS

We investigated a total of 119 consecutive patients who underwent distal gastrectomy with B-I or R-Y reconstruction for Stage I GC between 2006 and 2012. We retrospectively assessed the clinical data, including Hb results, of the first 2 years after surgery.

RESULTS

Compared with B-I reconstruction, R-Y reconstruction was performed more frequently in older patients (P = 0.017), and it was associated with a longer surgical duration (P < 0.001), a larger amount of blood loss (P = 0.031), a higher incidence of stasis (P = 0.044), and a greater decrease in Hb for the first 2 years after surgery. Univariate and multivariate analyses identified that R-Y reconstruction was the only risk factor (P = 0.0487; odds ratio = 2.755; 95% confidence interval = 1.01-7.91) for a decrease in Hb, independent of age, tumor location, postoperative complications, and other factors. In addition, an age ≥ 75 was identified as an independent risk factor for a decrease in Hb, particularly for patients underwent R-Y reconstruction (P = 0.033; odds ratio = 6.99; 95% confidence interval = 1.15-68.3) according to the multivariate analysis.

CONCLUSIONS

Billroth-I reconstruction might be preferable for the purpose of preventing a decrease in Hb in stage I GC patients, particularly in older patients.

Hypovitaminosis D in bariatric surgery: A systematic review of observational studies

BACKGROUND

Obesity is a public health problem that carries global and substantial social and economic burden. Relative to non-surgical interventions, bariatric surgery has the most substantial and lasting impact on weight loss. However, it leads to a number of nutritional deficiencies requiring long term supplementation.

OBJECTIVES

The aims of this paper are to review 25-hydroxyvitamin D [25(OH)D] status pre and post bariatric surgery, describe the dose response of vitamin D supplementation, and assess the effect of the surgical procedure on 25(OH)D level following supplementation.

METHODS

We searched Medline, PubMed, the Cochrane Library and EMBASE, for relevant observational studies published in English, from 2000 to April 2015. The identified references were reviewed, in duplicate and independently, by two reviewers.

RESULTS

We identified 51 eligible observational studies assessing 25(OH)D status pre and/or post bariatric surgery. Mean pre-surgery 25(OH)D level was below 30ng/ml in 29 studies, and 17 of these studies showed mean 25(OH)D levels ≤20ng/ml. Mean 25(OH)D levels remained below 30ng/ml following bariatric surgery, despite various vitamin D replacement regimens, with only few exceptions. The increase in post-operative 25(OH)D levels tended to parallel increments in vitamin D supplementation dose but varied widely across studies. An increase in 25(OH)D level by 9-13ng/ml was achieved when vitamin D deficiency was corrected using vitamin D replacement doses of 1100-7100IU/day, in addition to the usual maintenance equivalent daily dose of 400-2000IU (total equivalent daily dose 1500-9100IU). There was no difference in mean 25(OH)D level following supplementation between malabsorptive/combination procedures and restrictive procedures.

CONCLUSION

Hypovitaminosisis D persists in obese patients undergoing bariatric surgery, despite various vitamin D supplementation regimens. Further research is needed to determine the optimal vitamin D dose to reach desirable 25(OH)D levels in this population, and to demonstrate whether this dose varies according to the surgical procedure.

Endocrine and metabolic complications after bariatric surgery

Bariatric surgery is the most effective therapeutic option for obese patients; however, it carries substantial risks, including procedure-related complications, malabsorption, and hormonal disturbance. Recent years have seen an increase in the bariatric surgeries performed utilizing either an independent or a combination of restrictive and malabsorptive procedures. We review some complications of bariatric procedures more specifically, hypoglycemia and osteoporosis, the recommended preoperative assessment and then regular follow up, and the therapeutic options. Surgeon, internist, and the patient must be aware of the multiple risks of this kind of surgery and the needed assessment and follow up.

Skeletal effects of bariatric surgery: examining bone loss, potential mechanisms and clinical relevance

Bariatric surgery is the most effective therapeutic approach to morbid obesity, resulting in substantial weight loss and improved cardiometabolic profiles; however, a growing body of evidence suggests that bariatric procedures increase both skeletal fragility and the risk of related future fracture secondary to excessive bone loss. Prospective evidence shows that areal bone mineral density (BMD) assessed by dual energy X-ray absorptiometry (DXA) declines by as much as 14% in the proximal femoral regions, including the femoral neck and total hip, 12 months postoperatively. Lumbar spine areal BMD outcomes show greater 12-month postoperative variability across surgical procedures (-8 to +6%) and contrast with no change in volumetric BMD outcomes measured by quantitative computed tomography. Diminished mechanical loading, micronutrient deficiency and malabsorption, along with neurohormonal alterations, offer plausible underlying mechanisms to explain these observed post-bariatric bone changes, but most remain largely unsubstantiated in this population. Importantly, DXA-based skeletal imaging may have limited utility in accurately detecting bone change in people undergoing bariatric surgery; partly because excessive tissue overlying bone increases the variability of areal BMD outcomes. Moreover, a paucity of fracture and osteoporosis incidence data raises questions about whether marked post-bariatric surgery bone loss is clinically relevant or a functional adaptation to skeletal unloading. Future studies that use technology which is able to accurately capture the site-specific volumetric BMD and bone architectural changes that underpin bone strength in people undergoing bariatric surgery, that consider mechanical load, and that better quantify long-term fracture and osteoporosis incidence are necessary to understand the actual skeletal effects of bariatric surgery.

Fracture risk following bariatric surgery: a population-based study

The effects of bariatric surgery on skeletal health are poorly understood. We found that bariatric surgery patients are more prone to fracture when compared to the general population. While further studies of fracture risk in this population are needed, bone health should be discussed in bariatric surgery clinics.

INTRODUCTION

Bariatric surgery is an increasingly common treatment for medically complicated obesity. Adverse skeletal changes after bariatric surgery have been reported, but their clinical importance remains unknown. We hypothesized that bariatric surgery patients are at increased risk of fracture.

METHODS

We conducted a historical cohort study of fracture incidence among 258 Olmsted County, Minnesota, residents who underwent a first bariatric surgery in 1985-2004. Relative fracture risk was expressed as standardized incidence ratios (SIRs), while potential risk factors were evaluated by hazard ratios (HR) obtained from a time-to-fracture regression model.

RESULTS

The mean (±SD) body mass index at bariatric surgery was 49.0 ± 8.4 kg/m(2), with an average age of 44 ± 10 years and 82% (212) females. Gastric bypass surgery was performed in 94% of cases. Median follow-up was 7.7 years (range, 6 days to 25 years), during which 79 subjects experienced 132 fractures. Relative risk for any fracture was increased 2.3-fold (95% confidence interval (CI), 1.8-2.8) and was elevated for a first fracture at the hip, spine, wrist, or humerus (SIR, 1.9; 95% CI, 1.1-2.9), as well as for a first fracture at any other site (SIR, 2.5; 95% CI, 2.0-3.2). Better preoperative activity status was associated with a lower age-adjusted risk (HR, 0.4; 95% CI, 0.2-0.8) while prior fracture history was not associated with postoperative fracture risk.

CONCLUSIONS

Bariatric surgery, which is accompanied by substantial biochemical, hormonal, and mechanical changes, is associated with an increased risk of fracture.

Nutrient deficiencies after gastric bypass surgery

Bariatric surgery, and in particular, gastric bypass, is an increasingly utilized and successful approach for long-term treatment of obesity and amelioration of comorbidities. Nutrient deficiencies after surgery are common and have multiple causes. Preoperative factors include obesity, which appears to be associated with risk for several nutrient deficiencies, and preoperative weight loss. Postoperatively, reduced food intake, suboptimal dietary quality, altered digestion and absorption, and nonadherence with supplementation regimens contribute to risk of deficiency. The most common clinically relevant micronutrient deficiencies after gastric bypass include thiamine, vitamin B₁₂, vitamin D, iron, and copper. Reports of deficiencies of many other nutrients, some with severe clinical manifestations, are relatively sporadic. Diet and multivitamin use are unlikely to consistently prevent deficiency, thus supplementation with additional specific nutrients is often needed. Though optimal supplement regimens are not yet defined, most micronutrient deficiencies after gastric bypass currently can be prevented or treated by appropriate supplementation.

Adherence to vitamin supplementation following adolescent bariatric surgery

OBJECTIVE

Adolescents with extreme obesity, who have undergone bariatric surgery, must adhere to many lifestyle and nutritional recommendations, including multivitamin therapy. Little is known about multivitamin adherence following adolescent bariatric surgery.

DESIGN AND METHODS

The present study aims to document self-reported and electronically-monitored adherence to multivitamins, determine convergence between self-report and electronic monitoring adherence for multivitamins, and identify barriers to multivitamin adherence for adolescents who have undergone bariatric surgery.

RESULTS

The study used a prospective, longitudinal observational design to assess subjective (self-reported) and objective (electronic monitors) multivitamin adherence in a cohort of 41 adolescents (Mean age = 17.1 ± 1.5; range = 13-19) who have undergone bariatric surgery at Cincinnati Children's Hospital Medical Center. Mean adherence as derived from electronic monitoring for the entire 6-month study period was 29.8% ± 23.9. Self-reported adherence was significantly higher than electronically monitored adherence across both the 1 and 6-month assessment points (z = 4.5, P < 0.000 and z = 4.0, P < 0.0001, respectively). Forgetting and difficulty swallowing multivitamins were the two primary barriers identified. While there are no established data regarding best practice for multivitamins following bariatric surgery, high rates of nonadherence to multivitamin therapy were observed in adolescents who had undergone bariatric surgery with forgetting and difficulty swallowing pills as reported barriers to adherence.

CONCLUSION

These high rates of nonadherence to multivitamin therapy should be considered when devising treatment and family education pathways for adolescents considering weight loss surgery.

Metabolic syndrome, obesity and kidney stones

OBJECTIVES

To give a comprehensive and focused overview on the current knowledge of the causal relations of metabolic syndrome and/or central obesity with kidney stone formation.

METHODS

Previous reports were reviewed using PubMed, with a strict focus on the keywords (single or combinations thereof): urolithiasis, nephrolithiasis, kidney stones, obesity, metabolic syndrome, bariatric surgery, calcium oxalate stones, hyperoxaluria, insulin resistance, uric acid stones, acid-base metabolism.

RESULTS

Obesity (a body mass index, BMI, of >30 kg/m(2)) affects 10-27% of men and up to 38% of women in European countries. Worldwide, >300 million people are estimated to be obese. Epidemiologically, a greater BMI, greater weight, larger waist circumference and major weight gain are independently associated with an increased risk of renal stone formation, both for calcium oxalate and uric acid stone disease.

CONCLUSIONS

There are two distinct metabolic conditions accounting for kidney stone formation in patients with metabolic syndrome/central obesity. (i) Abdominal obesity predisposes to insulin resistance, which at the renal level causes reduced urinary ammonium excretion and thus a low urinary pH; the consequence is a greater risk of uric acid stone formation. (ii) Bariatric surgery, the only intervention that facilitates significant weight loss in morbidly obese people, carries a greater risk of calcium oxalate nephrolithiasis. The underlying pathophysiological mechanisms are profound enteric hyperoxaluria due to intestinal binding of calcium by malabsorbed fatty acids, and severe hypocitraturia due to soft or watery stools, which lead to chronic bicarbonate losses and intracellular metabolic acidosis.

Metabolic bone disease in the bariatric surgery patient

Bariatric surgery has proven to be a life-saving measure for some, but for others it has precipitated a plethora of metabolic complications ranging from mild to life-threatening, sometimes to the point of requiring surgical revision. Obesity was previously thought to be bone protective, but this is indeed not the case. Morbidly obese individuals are at risk for metabolic bone disease (MBD) due to chronic vitamin D deficiency, inadequate calcium intake, sedentary lifestyle, chronic dieting, underlying chronic diseases, and the use of certain medications used to treat those diseases. After bariatric surgery, the risk for bone-related problems is even greater, owing to severely restricted intake, malabsorption, poor compliance with prescribed supplements, and dramatic weight loss. Patients presenting for bariatric surgery should be evaluated for MBD and receive appropriate presurgical interventions. Furthermore, every patient who has undergone bariatric surgery should receive meticulous lifetime monitoring, as the risk for developing MBD remains ever present.

Managing medical and surgical disorders after divided Roux-en-Y gastric bypass surgery

The National Longitudinal Study of Adolescent Health and the National Health and Nutrition Examination Survey reported that over 40% of the US population is overweight. The average weight loss attained by medical management programs is neither sufficient nor durable enough to treat medically complicated obesity. An estimated 220,000 bariatric procedures are performed yearly in the USA and Canada. The divided Roux-en-Y gastric bypass (RYGB) is performed most commonly in these countries and is considered the gold standard bariatric surgical procedure. The complexity of RYGB means that serious and potentially preventable perioperative complications can occur. RYGB alters the normal anatomy and physiology of the upper gut, which has predictable adverse effects and potential complications. Patients seek advice and care for symptoms that develop or persist after RYGB; although some symptoms are expected and predictable, others are complications that may or may not require active medical or surgical intervention. Physicians should be able to predict and manage most postoperative medical and nutritional disorders related to RYGB and should be prepared to assess patients for potential referral for surgical intervention or revision.

Nutritional deficiencies in obesity and after bariatric surgery

The presence of nutritional deficiencies in overweight and obesity may seem paradoxical in light of excess caloric intake, but several micronutrient deficiencies appear to be higher in prevalence in overweight and obese adults and children. Causes are multifactorial and include decreased consumption of fruits and vegetables, increased intake of high-calorie, but nutritionally poor-quality foods, and increased adiposity, which may influence the storage and availability of some nutrients. As the obesity epidemic continues unabated and the popularity of bariatric surgery rises for severely obese adults and adolescents, medical practitioners must be aware of pre-existing nutritional deficiencies in overweight and obese patients and appropriately recognize and treat common and rare nutritional deficiencies that may arise or worsen following bariatric surgery. This article reviews current knowledge of nutritional deficits in obese and overweight individuals and those that commonly present after bariatric surgery and summarizes current recommendations for screening and supplementation.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist health-care professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.

Finding the optimal dose of vitamin D following Roux-en-Y gastric bypass: a prospective, randomized pilot clinical trial

BACKGROUND

Vitamin D deficiency is common following bariatric surgery and is due to a combination of baseline deficiency and postoperative malabsorption. There are few prospective studies evaluating the appropriate dose of vitamin D to prevent and treat vitamin D deficiency following bariatric surgery.

METHODS

We evaluated three doses of vitamin D3 (800, 2,000, and 5,000 IU/day) in a prospective, randomized pilot trial of 45 patients undergoing Roux-en-Y gastric bypass. Serum 25 hydroxy Vitamin D (25OHD), intact PTH (iPTH), calcium, and urine calcium/creatinine ratios were measured at 6, 12, and 24 months postoperatively. Due to a high dropout rate at 24 months, we focus on the 12-month data.

RESULTS

At 12 months, the 800-, 2,000-, and 5,000-IU groups had a mean +/- SD increase in 25OHD of 27.5 +/- 40.0, 60.2 +/- 37.4, and 66.1 +/- 42.2 nmol/L, respectively (p = 0.09) with a maximum increase in each group of 87.4, 114.8, and 129.8 nmol/L. Forty-four percent, 78%, and 70% achieved 25OHD levels >or=75 nmol/L (p = 0.38). Results for the 6- and 24-month time points were similar to the 12-month results. Mean weight loss at 24 months of the study was not different among groups (p = 0.52). Serum calcium did not change significantly, and there were no cases of hypercalcemia or sustained hypercalciuria.

CONCLUSIONS

Higher doses of vitamin D supplementation trend towards higher levels of 25OHD. Vitamin D replacement as high as 5,000 IU /day is safe and necessary in many patients to treat vitamin D deficiency following Roux-en-Y gastric bypass yet is still suboptimal in others.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist healthcare professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.

Treatment of vitamin D depletion after Roux-en-Y gastric bypass: a randomized prospective clinical trial

BACKGROUND

A high prevalence (60%) of vitamin D (VitD) depletion, defined as a serum 25-hydroxyvitamin D level of < or =20 ng/mL, is present in preoperative morbidly obese patients. Despite daily supplementation with 800 IU VitD and 1500 mg calcium after Roux-en-Y gastric bypass (RYGB), VitD depletion persists in almost one half (44%) of patients. However, the optimal management of VitD depletion after RYGB and the potential benefits of such treatment are currently unknown.

METHODS

A total of 60 VitD-depleted morbidly obese women were randomly assigned to receive 50,000 IU of VitD weekly after RYGB (group 1; n = 30) or no additional VitD after RYGB (group 2; n = 30). All patients received a daily supplement of 800 IU VitD and 1500 mg calcium. The serum calcium, parathyroid hormone, 25-hydroxyvitamin D, bone-specific alkaline phosphatase, urinary N-telopeptide, and bone mineral density were measured preoperatively and 1 year after RYGB. Questionnaires were used to assess other potential sources of VitD, including sunlight exposure and ingestion of VitD-containing foods/liquids.

RESULTS

At 1 year after RYGB, VitD depletion and mean 25-hydroxyvitamin D level had improved significantly in group 1 (14% and 37.8 ng/mL, respectively) compared with the values in group 2 (85% and 15.2 ng/mL, respectively; P <.001 for both). A significant 33% retardation in hip bone mineral density decline (P = .043) and a significantly greater resolution of hypertension was seen in group 1 (75% versus 32%; P = .029). No significant adverse effects were encountered from pharmacologic VitD therapy.

CONCLUSION

The results of our study have shown that 50,000 IU of VitD weekly after RYGB safely corrects VitD depletion in most women, attenuates cortical bone loss, and improves resolution of hypertension.

Nephrolithiasis after bariatric surgery for obesity

Surgical intervention has become an accepted therapeutic alternative for the patient with medically complicated obesity. Multiple investigators have reported significant and sustained weight loss after bariatric surgery that is associated with improvement of many weight-related medical comorbidities, and statistically significant decreased overall mortality for surgically treated as compared with medically treated subjects. Although the Roux-en-Y gastric bypass (RYGB) is considered an acceptably safe treatment, an increasing number of patients are being recognized with nephrolithiasis after this, the most common bariatric surgery currently performed. The main risk factor appears to be hyperoxaluria, although low urine volume and citrate concentrations may contribute. The incidence of these urinary risk factors among the total post-RYGB population is unknown, but may be more than previously suspected based on small pilot studies. The etiology of the hyperoxaluria is unknown, but may be related to subtle and seemingly subclinical fat malabsorption. Clearly, further study is needed, especially to define better treatment options than the standard advice for a low-fat, low-oxalate diet, and use of calcium as an oxalate binder.

Roux-en-Y gastric bypass is associated with early increased risk factors for development of calcium oxalate nephrolithiasis

BACKGROUND

Patients treated for obesity with jejunoileal bypass (JIB) experienced a marked increased risk of hyperoxaluria, nephrolithiasis, and oxalate nephropathy developing. Jejunoileal bypass has been abandoned and replaced with other options, including Roux-en-Y gastric bypass (RYGB). Changes in urinary lithogenic risk factors after RYGB are currently unknown. Our purpose was to determine whether RYGB is associated with elevated risk of developing calcium oxalate stone formation through increased urinary oxalate excretion and relative supersaturation of calcium oxalate.

STUDY DESIGN

A prospective longitudinal cohort study of 24 morbidly obese adults (9 men and 15 women) recruited from a university-based bariatric surgery clinic scheduled to undergo RYGB between December 2005 and April 2007. Patients provided 24-hour urine collections for analysis 7 days before and 90 days after operation. Primary outcomes were changes in 24-hour urinary oxalate excretion and relative supersaturation of calcium oxalate from baseline to 3 months post-RYGB.

RESULTS

Compared with their baseline, patients undergoing RYGB had increased urinary oxalate excretion (31 +/- 10 mg/d versus 41 +/- 18 mg/d; p = 0.026) and relative supersaturation of calcium oxalate (1.73 +/- 0.81 versus 3.47 +/- 2.59; p = 0.030) 3 months post-RYGB in six patients (25%). De novo hyperoxaluria developed. There were no preoperative patient characteristics predictive of development of de novo hyperoxaluria or the magnitude of change of daily oxalate excretion.

CONCLUSIONS

This prospective study indicates that RYGB is associated with an earlier increase in urinary oxalate excretion and relative supersaturation of calcium oxalate than previously reported. Additional studies are needed to determine longterm post-RYGB changes in urinary oxalate excretion and identify patients that might be at risk for hyperoxaluria developing.

Vitamin D and the bariatric surgical patient: a review

OBJECTIVE

Adiposity has been inversely associated with vitamin D concentration across a range of body mass index values and cultural groups. As obesity has increased markedly worldwide, a greater number of patients with severe obesity have been treated with gastric restrictive and/or malabsorptive surgical procedures. The purpose of this review was to describe current knowledge about vitamin D and severe obesity, and the impact of obesity surgery on vitamin D status.

RESEARCH METHODS AND PROCEDURES

A systematic review was conducted with search terms obesity, vitamin D, osteoporosis, bone disease, gastric bypass, and obesity surgery in various combinations. Publications were limited to those since 2000 to control for similarity in vitamin D assays and obesity prevalence levels.

RESULTS

Mean 25-hydroxy vitamin D was <80 nmol/l in more than 1,900 patients preoperatively, and was not restored to the optimal concentration of >80 nmol/l postoperatively. Both secondary hyperparathyroidism and bone loss were common, particularly when the obesity surgery included a malabsorptive component. Standard postsurgical supplementation with vitamin D and calcium have not been adequate to suppress secondary hyperparathyroidism or to restore 25-hydroxy vitamin D status.

DISCUSSION

The mechanisms behind vitamin D deficiency in severe obesity and evidence-based corrective actions have not been well-defined. Of particular concern are adolescents who qualify for and elect surgical treatment of their obesity, where subsequent metabolic bone disease may be long-standing.

Prevalence of vitamin D insufficiency and deficiency in morbidly obese patients: a comparison with non-obese controls

BACKGROUND

Vitamin D deficiency is common in patients after bariatric surgery. However, obesity itself has also been associated with decreased vitamin D. The prevalence of vitamin D deficiency in obese persons has not previously been compared to non-obese controls when controlling for factors that could affect vitamin D status.

METHODS

We evaluated 25 hydroxy vitamin D, iPTH, calcium, albumin, and creatinine in 41 patients undergoing Roux-en-Y gastric bypass. We then compared them to healthy non-obese controls matched for age, sex, race/ethnicity, and season of vitamin D measurement.

RESULTS

Ninety percent of the pre-bariatric surgery patients had 25-OH-D levels <75 nmol/l, and 61% had 25-OH-D levels <50 nmol/l versus 32 and 12% in controls, respectively. Additionally, 49% of the pre-bariatric surgery patients had secondary hyperparathyroidism versus 2% of controls. These differences persisted after controlling for sunlight exposure and dietary intake of calcium and vitamin D. Mean calcium, corrected for albumin, and creatinine were not significantly different between the groups, but mean albumin levels were significantly lower among surgery patients.

CONCLUSION

Vitamin D deficiency is common in obese patients at the time of bariatric surgery and is also accompanied by secondary hyperparathyroidism approximately half the time. These findings suggest that vitamin D deficiency after bariatric surgery is multifactorial and in part caused by preoperative vitamin D deficiency rather than postoperative malabsorption alone. In this study, increased vitamin D deficiency in obese persons cannot be explained by a difference in calcium/vitamin D intake or sunlight exposure.

Bone loss. An emerging problem following obesity surgery

The incidence of obesity worldwide has increased markedly in the past 2 decades, with estimates of increases of 50% in the United States alone. Research indicates that weight loss produced by diet alone is not sustained and that 75% of dieters regain most of the weight lost within 1 year and 90% within 2 years. Morbid obesity is associated with comorbid conditions, including heart disease, hypertension, diabetes, mechanical arthropathy, sleep apnea, and numerous other serious disorders and a shortened life expectancy. Because of limited success with medical management, surgical treatment of morbid obesity has been used increasingly, especially with the development of laparoscopic procedures, including Roux-en-Y gastric bypass (RYGB). RYGB is associated with low surgical mortality, marked decreased food intake, and significant, sustained weight loss. However, in this emerging, unique population there is growing appreciation that these procedures may be associated with the development of bone loss and skeletal fragility because of altered nutrient metabolism. Despite the threat of skeletal fragility and fracture, there is limited data addressing the effects of bariatric surgery on bone metabolism and bone loss.

[Nutritional deficiencies associated with bariatric surgery]

Morbidly obese patients often have nutritional deficiencies, particularly in fat-soluble vitamins, folic acid and zinc. After bariatric surgery, these deficiencies may increase and others can appear, especially because of the limitation of food intake in gastric reduction surgery and of malabsorption in by-pass procedures. The latter result in more important weight loss but also increase the risk of more severe deficiencies. The protein deficiency associated with a decrease in the fat-free mass has been described in both procedures. It can sometimes require an enteral or parenteral support. Anemia can be secondary to iron deficiency, folic acid deficiency and even to vitamin B12 deficiency. Neurological disorders such as Gayet-Wernicke encephalopathy due to thiamine deficiency, or peripheral neuropathies may also be observed. Malabsorption of fat-soluble vitamins and other nutrients, especially if diagnosed after by-pass surgery, rarely cause clinical symptoms. However, some complications have been reported such as bone demineralization due to vitamin D deficiency, hair loss secondary to zinc deficiency or hemeralopia from vitamin A deficiency. A careful nutritional follow-up should be performed during pregnancy after obesity surgery, because possible deficiencies can affect the health of both the mother and child. In conclusion, increased awareness of the risk of deficiency and the systematic dosage of micronutrients are needed in the pre- and postoperative period in obese patients undergoing bariatric surgery. The case by case correction of these deficiencies is mandatory, and their systematic prevention should be evaluated.

Nutritional consequences of weight-loss surgery

Nutritional deficiencies are already present in many morbidly obese patients before weight-loss surgery. Appropriate preoperative detection and correction is essential. The severity and pattern of deficiencies is dependent on the presence of preoperative uncorrected deficiency, the type of procedure performed varying with the degree of restriction or the length of bypassed small intestine, the modification of eating behavior, the development of complications, compliance with oral multivitamin and mineral supplementation, and compliance with follow-up. Rigorous control of fluids and electrolytes with establishment of adequate oral nutrition is important in the immediate postoperative period. Regular follow-up of the metabolic and nutritional status of the patient is essential, with life-long multivitamin and mineral supplementation.

Hyperoxaluric nephrolithiasis is a complication of Roux-en-Y gastric bypass surgery

Roux-en-Y bypass surgery is the most common bariatric procedure currently performed in the United States for medically complicated obesity. Although this leads to a marked and sustained weight loss, we have identified an increasing number of patients with episodes of nephrolithiasis afterwards. We describe a case series of 60 patients seen at Mayo Clinic-Rochester that developed nephrolithiasis after Roux-en-Y gastric bypass (RYGB), including a subset of 31 patients who had undergone metabolic evaluation in the Mayo Stone Clinic. The mean body mass index of the patients before procedure was 57 kg/m(2) with a mean decrease of 20 kg/m(2) at the time of the stone event, which averaged 2.2 years post-procedure. When analyzed, calcium oxalate stones were found in 19 and mixed calcium oxalate/uric acid stones in two patients. Hyperoxaluria was a prevalent factor even in patients without a prior history of nephrolithiasis, and usually presented more than 6 months after the procedure. Calcium oxalate supersaturation, however, was equally high in patients less than 6 months post-procedure due to lower urine volumes. In a small random sampling of patients undergoing this bypass procedure, hyperoxaluria was rare preoperatively but common 12 months after surgery. We conclude that hyperoxaluria is a potential complicating factor of RYGB surgery manifested as a risk for calcium oxalate stones.