Assessment of Mortality in Patients Enrolled in a Risedronate Clinical Trial Program: A Retrospective Cohort Study

Risedronate, a pyridinyl bisphosphonate, has been shown in large clinical trials to be effective in the prevention and treatment of osteoporosis. Analysis of safety data from these trials has shown that risedronate (2.5- and 5-mg doses) has an overall safety profile comparable to placebo during the course of the clinical trials. The clinical trials were powered appropriately to analyze the efficacy endpoints; however, patients were not systematically followed after completion of the clinical trials and therefore vital status for most of the patient cohort after the cessation of the clinical trials was unknown. In order to investigate further the safety profile of risedronate observed in the clinical trials database, we conducted a retrospective cohort mortality study among 7981 patients comprising the intent-to-treat population in three North American risedronate osteoporosis trials. No difference in all cause mortality was observed in patients receiving risedronate treatment compared with patients receiving placebo. There were also no differences between these groups in mortality due to all cancers, lung cancer, and gastrointestinal tract cancer. A trend toward lower cardiovascular mortality was observed in the risedronate groups compared with placebo; this difference was largely due to a significant reduction in stroke mortality in the active treatment groups. Follow-up mortality data in this retrospective cohort study demonstrate that treatment with risedronate has no effect on overall mortality rates.