Abstract T P313: Sensitivity of ICD-9 Discharge Codes to Identify TIA Cases in 4 Community-Based Emergency Departments
Introduction: The diagnosis of TIA is often challenging in the emergency department (ED) setting. ICD-9 discharge code 435 is often used to identify TIA cases; however, its accuracy is unclear. Our objective was to determine the sensitivity of ICD-9 code 435 to identify confirmed TIA cases treated in 4 community-based EDs.
Methods: Over a 12 month period suspect TIA cases were prospectively identified using hot-pursuit mechanisms in 4 EDs. A time-based definition of TIA was used (i.e., acute onset focal unilateral symptoms with duration <24 hours and no alternative diagnosis). All cases had a final clinical diagnosis of TIA confirmed following an independent physician panel review. Data were abstracted from medical charts and the primary ICD-9 discharge code was obtained from the hospital or ED billing records. ICD-9 discharge codes were neither used to identify cases or confirm the final diagnosis.
Results: Of 366 subjects with suspected TIA, 336 (92%) had a confirmed final diagnosis of TIA. Mean age was 66 years, 54% female, 31% non-white and 83% were hospitalized. The relative frequency of primary ICD-9 discharge codes at each of the 4 EDs are shown in the Table. The overall sensitivity of the 435 code was 64.3% (95% CI 58.9-69.4). Alternative codes used included stroke-related (8.0%), other CVD-related (2.7%), miscellaneous (8.3%) and non-specific symptoms codes (16.7%). The frequency of 435 coding varied non-significantly between sites (56% to 72%; p= 0.13); however, sites varied substantially in their use of non-specific symptoms codes (4.8% to 26.7%; p=0.002).
Conclusions: In this series of confirmed TIA cases, more than 1/3rd would not have been identified if the 435 code was used. These findings suggest that the 435 code should not be relied upon to identify TIA cases. Future studies should determine the causes of the variation in coding between sites, and also measure both sensitivity and specificity of the 435 code.
Author Disclosures: M.J. Reeves: None. M. Nasiri: None. T. Glynn: None. M. Hughes: None. R. Kothari: None. J.A. Oostema: None. M. Brown: None.
- © 2014 by American Heart Association, Inc.