Endoscopic comparison of esophageal and gastroduodenal effects of risedronate and alendronate in postmenopausal women

Background & Aims: Bisphosphonates are effective treatment for osteoporosis, but upper gastrointestinal injury associated with some compounds has caused concern. This study compared the incidence of gastric ulcers after treatment with risedronate, a pyridinyl bisphosphonate, and alendronate, a primary amino bisphosphonate. Esophageal and gastroduodenal injury assessed by endoscopy scores was a secondary endpoint. Methods: Healthy, postmenopausal women (n = 515) received 5 mg risedronate (n = 255) or 10 mg alendronate (n = 260) for 2 weeks. At baseline and on days 8 and 15, subjects underwent endoscopy and evaluator-blinded assessment of the esophageal, gastric, and duodenal mucosa. Results: Gastric ulcers were observed during the treatment period in 9 of 221 (4.1%) evaluable subjects in the risedronate group compared with 30 of 227 (13.2%) in the alendronate group (P < 0.001). Mean gastric endoscopy scores for the risedronate group were lower than those for the alendronate group at days 8 and 15 (P less than or equal to 0.001). Mean esophageal and duodenal endoscopy scores were similar in the 2 groups at days 8 and 15. Esophageal ulcers were noted in 3 evaluable subjects in the alendronate group, compared with none in the risedronate group, and duodenal ulcers were noted in 1 evaluable subject in the alendronate group and 2 in the risedronate group. Conclusions: At doses used for the treatment of osteoporosis, risedronate was associated with a significantly lower incidence of gastric ulcers than alendronate. These findings confirm that bisphosphonates differ in their potential to damage the gastroesophageal mucosa.