Metabolic bone disease after gastric bypass surgery for obesity

Background: The popularity of gastric bypass surgery for treatment of morbid obesity has been increasing in recent years. Osteomalacia and osteoporosis are commonly observed in patients who have had partial gastric resections for treatment of peptic ulcer disease. Recently, we encountered four patients with previous gastric bypass surgery who had metabolic bone disease similar to that reported in the older literature in patients who had partial gastrectomies. Methods: Review of clinical data of four patients who developed osteomalacia and osteoporosis 9 to 12 years after gastric bypass surgery for morbid obesity. Results: All subjects were women, 43 to 58 years old. Three had Roux-en-Y gastric bypass, and the other had a biliopancreatic diversion 9 to 12 years prior to presentation. Weight loss averaged 41.8 kg. Patients reported fatigue, myalgias, and arthralgias. They had symptoms for many months or years before the correct diagnosis was established. All were osteopenic or osteoporotic with hypocalcemia, very low or undetectable 25-hydroxyvitamin D levels, secondary hyperparathyroidism, increased 1,25-dihydroxyvitamin D levels, and increased serum alkaline phosphatase. Conclusions: Relatively little has been published in the general medical literature about this postoperative complication of bariatric surgery. Yet, nearly all patients after bariatric surgery will receive their long-term follow-up from a primary care physician. Physicians and patients need to be aware of this complication and take measures to identify and prevent it.