Is there an association between urolithiasis and Roux-en-y gastric bypass surgery?

Association of Kidney Stone Disease (KSD) with Primary Gastrointestinal Surgery: a Systematic Review over Last 2 Decades

PURPOSE OF REVIEW

We aim to provide an up-to-date literature review to further characterise the association of kidney stone disease (KSD) with gastrointestinal (GI) surgery. As KSD is associated with significant morbidity, it is important to quantify and qualify this association to provide better care and management for the patient subgroup.

OBJECTIVE

To perform a systematic review of the existing literature to evaluate the association of KSD following GI surgery.

METHODS

A literature search was performed of the following databases: MEDLINE, EMBASE, Scopus, Google Scholar, Key Urology, Uptodate and Cochrane Trials from January 2000 to June 2020.

RECENT FINDINGS

A total of 106 articles were identified, and after screening for titles, abstracts and full articles, 12 full papers were included. This involved a total of 9299 patients who underwent primary GI surgery. Over a mean follow-up period of 5.4 years (range: 1-14.4 years), 819 (8.8%) developed KSD, varying from 1.2 to 83% across studies. The mean time to stone formation was approximately 3 years (range: 0.5-9 years). In the 4 studies that reported on the management of KSD (n = 427), 38.6% went on to have urological intervention. There is a high incidence of KSD following primary GI surgery, and after a mean follow-up of 3 years, around 9% of patients developed KSD. While the GI surgery was done for obesity, inflammatory bowel disease or cancer, the risk of KSD should be kept in mind during follow-up, and prompt urology involvement with metabolic assessment, medical and or surgical management offered as applicable.

Pathophysiology and Treatment of Enteric Hyperoxaluria

Enteric hyperoxaluria is a distinct entity that can occur as a result of a diverse set of gastrointestinal disorders that promote fat malabsorption. This, in turn, leads to excess absorption of dietary oxalate and increased urinary oxalate excretion. Hyperoxaluria increases the risk of kidney stones and, in more severe cases, CKD and even kidney failure. The prevalence of enteric hyperoxaluria has increased over recent decades, largely because of the increased use of malabsorptive bariatric surgical procedures for medically complicated obesity. This systematic review of enteric hyperoxaluria was completed as part of a Kidney Health Initiative-sponsored project to describe enteric hyperoxaluria pathophysiology, causes, outcomes, and therapies. Current therapeutic options are limited to correcting the underlying gastrointestinal disorder, intensive dietary modifications, and use of calcium salts to bind oxalate in the gut. Evidence for the effect of these treatments on clinically significant outcomes, including kidney stone events or CKD, is currently lacking. Thus, further research is needed to better define the precise factors that influence risk of adverse outcomes, the long-term efficacy of available treatment strategies, and to develop new therapeutic approaches.

Kidney Stones After Bariatric Surgery: Risk Assessment and Mitigation

Obesity is rampant across the spectrum of age, gender, and race in the Unites States. Paralleling this epidemic, kidney stone prevalence is also rising, affecting nearly 1 in 11 individuals. Bariatric surgical procedures, such as Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), are the most effective weight loss options for morbidly obese or severely obese individuals with comorbidities. A number of studies have linked kidney stone development to bariatric surgical history, particularly RYGB, which portends up to a threefold increase in calcium oxalate stone risk compared with age-matched, obese controls. Stone development after malabsorptive (RYGB) and restrictive (SG) bariatric procedures are driven primarily by alterations in 24-h urine profiles, such as increased urinary oxalate, decreased urine volume, and reduced urinary citrate levels-all of which have been linked to increased kidney stone risk. What clinical recommendations, if any, can be given to reduce kidney stone risk in bariatric kidney stone patients? This review provides not only updated stone incidence and 24-h urine data in this population, but also reassurance-the metabolic alterations that result from bariatric surgery can be successfully mitigated by increased provider awareness, patient education, and a combination of dietary and pharmacological adjustments.

[The profile of patients undergoing bariatric surgery in the Brazilian Unified National Health System: a systematic review]

Nearly one million Brazilians were morbidly obese in 2013. Bariatric surgery is an option for sustained weight loss, and the Brazilian Unified National Health System (SUS) had provided 50,000 such procedures as of 2014. The SUS database does not provide anthropometric and comorbidity data on these patients, so the aim of the current study was to perform a systematic review to assess the profile of SUS patients that underwent bariatric surgery from 1998 to 2014. The MEDLINE, LILACS, SciELO, and Scopus databases were searched, and the methodological quality of the included articles was assessed. Of the 1,591 identified studies, 39 were selected, 95% of which were observational. Patients had a mean age of 41.4 years and mean body mass index of 48.6kg/m2; 21% were males, 61% hypertensive, 22% diabetics, and 31% presented sleep apnea. When compared to international study samples, SUS patients showed similar a anthropometric profile and comorbidities but higher prevalence of hypertension. The studies' low methodological quality suggests caution in interpreting the results.

Kidney stone risk following modern bariatric surgery

Over the past 10 years, a variety of reports have linked bariatric surgery to metabolic changes that alter kidney stone risk. Most of these studies were retrospective, lacked appropriate controls, or involved bariatric patients with a variety of inclusion criteria. Despite these limitations, recent clinical and experimental research has contributed to our understanding of the pathophysiology of stone disease in this high-risk population. This review summarizes the urinary chemistry profiles that may be responsible for the increased kidney stone incidence seen in contemporary epidemiological bariatric studies, outlines the mechanisms of hyperoxaluria and potential therapies through a newly described experimental bariatric animal model, and provides a focused appraisal of recommendations for reducing stone risk in bariatric stone formers.