Bariatric Surgery and Effects on Calcium and Bone Metabolism

With the increasing epidemic of obesity in the United States as well as abroad, bariatric surgery has emerged as the most effective and sustained treatment for reduction. This treatment modality has been well recognized to diminish the risk of cardiovascular morbidity and mortality and ameliorate diabetes mellitus. However, with time, derangement in mineral metabolism has emerged as a major complication in this population. Population-based study has shown increased prevalence of bone fractures and kidney stone formation following bariatric surgery. The risk appears to be more specific after Roux-en-Y gastric bypass procedures, the most common surgical approach among this population. Over the past decade, there have been advances in the understanding of pathophysiologic mechanisms of both bone loss and kidney stone disease in these patients. The understanding of these underlying pathophysiologic mechanisms may lead to the development of drug therapies that ameliorate this complication. Unfortunately, at the present time, there is no hard data on any specific treatment showing decreased incidence of fragility fractures or kidney stone passage. However, some studies suggest that calcium and vitamin D supplementation may decrease bone loss and bone turnover, and as a result, increase bone mineral density in this population. However, there is concern with the development of kidney stone formation following such an approach. A novel treatment approach would be the use of effervescent potassium calcium citrate that not only prevents complications of bone loss but may diminish the risk of kidney stone formation. Despite preliminary results showing the effectiveness of this drug in the reduction in the parathyroid hormone, bone turnover, and improvement in the urinary saturation marker showing effectiveness against calcium oxalate and uric acid stones, there is no hard data available to support the effectiveness of this treatment in the reduction in fragility fractures or kidney stone incidence. Such studies to explore this effect must be considered in the future.