Bariatric surgery does not affect kidney stone disease

numerous epidemiological studies demonstrate the correlation between obesity and urolithiasis. Bariatric surgery is effective in significant weight loss, reducing mortality rates, and lowering the incidence of obesity-related comorbidities. However, it may be associated with long-term complications such as urolithiasis, with an estimated increase of 7.6% in bariatric patients. This study investigates the impact of various bariatric surgical techniques and personal and nutritional habits on post-operative urolithiasis.

185 patients were prospectively enrolled in the study. All patients underwent nutritional assessment two years after surgery, and urinary stone disease was evaluated through urinalysis. Patients with urinary crystals were subsequently sent to the division of Urology to evaluate the possible presence of urinary stones through an abdominal CT scan.

kidney stone disease was present in 12 female patients (12/ 185 - 6.49%) out of the 25 (12/25-48%) with urinary crystals. Among the various surgical techniques, 8 patients underwent SG, 2 patients each for OAGB and RYGB, without a proven significant correlation. Hypertension, Dyslipidemia, and OSAS were significantly correlated with the incidence of urolithiasis (p-value < 0.05). BMI > 30 kg/m2 was significantly correlated with urinary stone formation (p-value < 0.05).

patients undergoing bariatric surgery should receive counseling about the risk of developing urolithiasis (6.49%) independently from the surgical treatment, highlighting the necessity of adhering to nutritional guidelines. Evaluation for urinary stones could be recommended during follow-up, especially for patients with a BMI > 30 kg/m².