Validation of an Operational Definition to Identify Distal Radius Fractures in a National Health Insurance Database

To develop and validate identification criteria for distal radius fractures (DRFs) and their treatment using a national health insurance database. Patients who had at least 1 wrist radiograph taken in 2018 were recruited from a single academic referral hospital. After excluding patients who lacked immobilization code for wrist pathology, we collected data on the overall population. Because some patients might have undergone wrist radiography at another institution or had DRFs without an immobilization code, we additionally included patients who had a DRF diagnosis code at our institution. Reviews of medical records and wrist radiographs were considered for the diagnosis of DRF. We evaluated the sensitivity, specificity, and positive predictive value (PPV) of 3 operational definitions of fractures that were based on a single primary or secondary diagnosis code; all diagnosis codes, including primary and secondary codes; and all diagnosis and procedure codes. Among 768 patients included in the study, true DRFs were confirmed in 305. The sensitivity, specificity, and PPV for definition 1 were 91.5% (95% CI, 88.3%–94.6%), 97.5% (95% CI, 95.9%–99.1%), and 96.9% (95% CI, 94.9%–98.9%), respectively. Although the sensitivity of definition 2 was higher (92.1%; 95% CI, 89.1%–95.2%), its specificity and PPV were lower (96.4% [95% CI, 94.4%–98.3%] and 95.6% [95% CI, 93.2%–97.9%], respectively). The sensitivity of definition 3 was the lowest (88.2%; 95% CI, 84.6%–91.8%), but its specificity and PPV were the highest among the 3 definitions (98.6% [95% CI, 97.4%–98.8%] and 98.2% [95% CI, 96.6%–99.8%], respectively). Patients with DRFs can be identified from claims databases with high accuracy using an operational definition based on DRF diagnosis and procedure codes, including codes for surgical and nonoperative methods. Verified operational definitions will increase the consistency of results in future national health insurance database studies related to DRFs.