Validation Study of Claims-based Definitions of Suspected Atypical Femoral Fractures Using Clinical Information

Abstract

Introduction Bisphosphonates, one of the standard pharmacological treatments for osteoporosis, increase bone mineral density and reduce the risk of incident fracture by inhibition of osteoclast-薬剤疫学 Jpn J Pharmacoepidemiol, 21�1) June 2016：13 Shiro TANAKA ＊1 , Hiroshi HAGINO ＊2 , Akiko ISHIZUKA ＊3 , Teruhiko MIYAZAKI ＊3 , Takanori YAMAMOTO ＊4 , Takayuki HOSOI ＊5 〈Abstract〉 Objective: Monitoring the incidence of atypical femoral fractures（AFFs）using medical claim databases is useful to assess the safety of long-term bisphosphonate exposure. Therefore, we aimed to validate the relationship between clinically-defined suspected AFFs and the candidate patients obtained from claims data at three hospitals in Japan. Design: A cross-sectional study involving three hospitals that perform bone fracture surgery and from which electronic medical record databases of diagnoses and procedures are available. Methods: Candidate patients were at the medical databases using two International Classification of Diseases, 10th Edition（ICD-10）codes（subtrochanteric fracture and fracture of shaft of femur）in the claims databases. These potential cases by claim-based definition were validated using clinically-confirmed information such as, the patient operation records, the discharge records, or radiographic imaging findings as suspected AFFs. Results: Among fracture cases in the hospitals, and 9 cases with subtrochanteric fracture and 23 cases with femoral shaft fracture were identified based on the ICD-10 codes in the claims databases. Clinically confirmed subtrochanteric fracture had a sensitivity of 81.8％（95％ CI: 48.2-97.7％), and a specificity of 100.0％（95％ CI: 99.9-100.0％). For femoral shaft fracture, the sensitivity was 82.1％（95％ CI: 63.1-93.9％), and the specificity was 100.0％ （95％ CI: 99.9-100.0％). In subgroup analyses, the sensitivities in patients over the age of 50 years with a single fracture site and with osteoporosis were relatively higher than in other subgroups. Conclusion: The claims-based definitions of suspected AFFs are accurate, indicating the value of pharmacoepidemiological studies using the National Receipt Database. （Jpn J Pharmacoepidemiol 2016；21（1） ：13-19)