Accuracy of administrative data versus clinical data to evaluate carotid endarterectomy and carotid stenting.

OBJECTIVE: Administrative data have been used to compare carotid endarterectomy (CEA) and carotid artery stenting (CAS). However, there are limitations in defining symptom status, Centers for Medicare and Medicaid Services high-risk status, as well as complications. Therefore, we did a direct comparison between administrative data and physician chart review as well as between data collected for the National Surgical Quality Improvement Program (NSQIP) and physician chart review for CEA and CAS.
METHODS: We performed an outcomes analysis on all CEA and CAS procedures from 2005 to 2011. We obtained International Classification of Diseases, Ninth Revision diagnosis codes from hospital discharge records regarding symptom status, high-risk status, and perioperative stroke. We also obtained data on all CEA patients submitted to NSQIP over the same time period. One of the study authors (R.B.) then performed a chart review of the same patients to determine symptom status, high-risk status, and perioperative strokes and the results were compared.
RESULTS: We identified 1342 patients who underwent CEA or CAS between 2005 and 2011 and 392 patients who underwent CEA that were submitted to NSQIP. Administrative data identified fewer symptomatic patients (17.0% vs 34.0%), physiologic high-risk patients (9.3% vs 23.0%), and anatomic high-risk patients (0% vs 15.2%). Although administrative data identified a similar proportion of perioperative strokes (1.9% vs 2.0%), this was due to the fact that these data identified eight false positive and nine false negative perioperative strokes. NSQIP data identified more symptomatic patients compared with chart review (44.1% vs 30.3%), fewer physiologic high-risk patients (13.0% vs 18.6%), fewer anatomic high-risk patients (0% vs 6.6%), and a similar proportion of perioperative strokes (1.5% vs 1.8%, only one false negative stroke and no false positives).
CONCLUSIONS: Administrative data are unreliable for determining symptom status, high-risk status, and perioperative stroke and should not be used to analyze CEA and CAS. NSQIP data do not adequately identify high-risk patients, but do accurately identify perioperative strokes and to a lesser degree, symptom status.