The use of a large pharmacoepidemiological database to study exposure to oral corticosteroids and risk of fractures: Validation of study population and results

Purpose - The objective of this study was an evaluation of the sensitivity of findings of the relationship between oral corticosteroid use and the ris k of fracture. We found in earlier work that the risk of fracture was signi ficantly higher during oral corticosteroid treatment, with increases of 61% in hip and 160% in vertebral fractures. Methods - Information was obtained from the General Practice Research Datab ase which contains medical records of general practitioners in the UK. The study included 244,235 oral corticosteroid users and 244,235 controls. Results - The validation of fracture cases showed that the hip fractures, a s recorded in the GPRD, were confirmed by the GP on the questionnaire in 90 .7% of the cases and by discharge summary in 86.5%. The relative rate of no n-vertebral fracture during oral corticosteroid use did not vary substantia lly between patients with different diseases, age, or gender. The sensitivi ty analysis, modifying the type of analysis or inclusion of patients, did n ot materially change the findings. Conclusions - We found a high level of validity of the GPRD with respect to hip and vertebral fractures. The sensitivity analysis indicated internal v alidity and consistency of the findings on fracture risks of oral corticost eroid therapy. Copyright (C) 2000 John Wiley & Sons, Ltd.