Abstract 379: The Accuracy Of ICD-10 Discharge Diagnosis Codes For Identification Of Isolated Sub-Segmental Pulmonary Embolism: A PE-EHR+ Substudy

Introduction: International Classification of Diseases 10 th revision (ICD-10) discharge diagnosis codes are widely used for research studies that use electronic databases. The accuracy of the codes for identifying patients with isolated sub-segmental pulmonary embolism (issPE) is unknown. Methods: We used data from the Mass General Brigham (MGB) health system (01/2016-12/2021) and included 1,000 patients randomly selected from 3 groups: Patients with ICD-10 Principal Discharge Diagnosis codes for PE, patients with secondary Discharge Diagnosis codes for PE, and patients with no ICD-10 codes for PE. Weighted estimates were obtained by considering the total number of hospitalizations in each category at MGB hospitals. Accuracy of the codes was assessed by two independent physicians who reviewed discharge summaries, daily notes, and radiology reports. Results: Of 1,000 records reviewed, 993 were included (age: 62.4±17.0 years, 54.8% female). Manual chart review found 493 patients with acute PE, including 59 (12.0%) with issPE. Of these 59 patients, 58 (98.3%) had ICD-10 codes for PE. However, only in 8 (13.6%) cases, PE codes were specified as being limited to subsegmental vessels (issPE). In turn, 23 additional cases with Principal-or-secondary ICD-10 codes for issPE did not have acute issPE during index hospitalization per review of records. The sensitivity and specificity for issPE codes in Principal or secondary discharge position were 13.6% and 99.5% (Table, panel A). Positive predictive value in the weighted sample was 26.2% (Table, panel B). Conclusion: Although specificity and negative predictive value of ICD-10 codes in Principal-or-secondary discharge diagnosis position for issPE are excellent, sensitivity and positive predictive value are low, highlighting the need for revised algorithms or use of natural language processing for data sources that include radiology reports.