Long-term incidence of symptomatic urolithiasis post-bariatric surgery

Urinary Lithiasis Risk Assessment after Bariatric Surgery

Malabsorption is a consequence of gastric bypass (GB). GB increases the risk of kidney stone formation. This study aimed to evaluate the accuracy of a screening questionnaire for assessing the risk of lithiasis in this population. We performed a monocentric retrospective study to evaluate a screening questionnaire administered to patients who underwent gastric bypass surgery between 2014 and 2015. Patients were asked to answer a questionnaire that included 22 questions divided into four parts: medical history, episodes of renal colic before and after bypass surgery, and eating habits. A total of 143 patients were included in the study, and the mean age of the patients was 49.1 ± 10.8 years. The time between gastric bypass surgery and the completion of the questionnaire was 50.75 ± 4.95 months. The prevalence of kidney stones in the study population was 19.6%. We found that with a score of ≥6, the sensitivity and specificity were 92.9% and 76.5%, respectively. Positive and negative predictive values were 49.1% and 97.8%, respectively. The ROC curve showed an Area Under the Curve (AUC) of 0.932 ± 0.029 (p < 0.001). We developed a reliable and short questionnaire to identify patients at a high risk of kidney stones after gastric bypass. When the results of the questionnaire were equal to or greater than six, the patient was at a high risk of kidney stone formation. With a good predictive negative value, it could be used in daily practice to screen patients who have undergone gastric bypass and are at a high risk of renal lithiasis.

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.