Postmarketing surveillance rates of uveitis and scleritis with bisphosphonates among a national veteran cohort

PURPOSE: Uveitis and scleritis are the most serious ocular side effects of bisphosphonate therapy. The purpose of this study was to determine the 6-month rates of uveitis/scleritis following dispensing of bisphosphonates in a large veteran cohort. METHODS: Two national databases (clinical and pharmacy) for fiscal year (FY) 2006 were linked to identify new diagnoses of uveitis/scleritis following the initial dispensing of bisphosphonate drugs. New diagnoses in FY 2006 were identified using International Classification of Diseases, Version 9, Clinical Modification (ICD-9-CM), in a cohort of veterans without a previous diagnosis of uveitis or scleritis using a look-back period to FY 2005. The new diagnoses were temporally aligned with initial dispensing of bisphosphonates and the rates of new cases were calculated for 1-month and 6-month time intervals. RESULTS: There were 7.9 new cases of uveitis/scleritis per 10,000 individuals with a newly dispensed bisphosphonate that occurred within 180 days. The relative risk of uveitis/scleritis for 6 months was 1.23 (95% confidence interval: 0.85-1.79) compared to veterans not exposed to the medications. The rates of uveitis/scleritis did not differ significantly based on route of administration (oral or parenteral) or after age adjustment. Just over a third of the diagnoses were scleritis. Nearly 43% of patients with uveitis/scleritis after bisphosphonate use had a systemic diagnosis commonly associated with inflammation of the uveal tract or sclera. CONCLUSIONS: The 30-day and 6-month rates of uveitis/scleritis following the dispensing of a bisphosphonate drug are low and do not differ significantly from rates recorded for veterans not dispensed these drugs.