Comparison of Clinical Trials and Administrative Claims to Identify Stroke Among Patients Undergoing Aortic Valve Replacement: Findings From the EXTEND Study.

BACKGROUND: Cerebrovascular events (CVEs) are devastating complications after aortic valve replacement. We assessed whether billing claims accurately identify CVEs in place of clinical event adjudication in structural heart disease trials.
METHODS: Adult participants in the US CoreValve High Risk and SURTAVI trials (Surgical or Transcatheter Aortic-Valve Replacement in Intermediate-Risk Patients) were linked to Medicare inpatient claims from January 1, 2006 to December 31, 2016. Claims consistent with CVEs within 14 days of a similar trial-adjudicated CVE were considered a match. The sensitivity, specificity, and positive and negative predictive values of International Classification of Diseases, Ninth and Tenth Revisions, Clinical Modification billing codes for cerebrovascular disease were determined against trial-defined CVEs as the criterion standard. Kaplan-Meier estimates of claims-defined versus trial-defined CVEs were compared.
RESULTS: Among 4230 linked trial participants (linkage rate 79.8%), 550 (13.0%) sustained 630 adjudicated CVEs over a 5-year follow-up period. Linked and nonlinked individuals were similar. An algorithm using 4 International Classification of Diseases, Ninth Revision, Clinical Modification codes (434.91, 434.11, 433.11, and 997.02) had a sensitivity of 60.9%, specificity of 99.0%, positive predictive value of 86.5%, and negative predictive value of 95.8% for identifying a trial-adjudicated ischemic stroke. An algorithm using 3 International Classification of Diseases, Tenth Revision, Clinical Modification codes (I63.9, I63.40, I63.49) had a sensitivity of 66.7%, specificity of 99.4%, positive predictive value of 88.9%, and negative predictive value of 97.6%.
CONCLUSIONS: In linked clinical trial and Medicare claims data, 4 International Classification of Diseases, Ninth Revision, Clinical Modification and 3 International Classification of Diseases, Tenth Revision, Clinical Modification billing codes identified half of trial-adjudicated CVEs during follow-up with high specificity and predictive value, but imperfect sensitivity. Although low sensitivity may limit the use of claims to substitute for traditional trial outcomes to identify CVEs, high specificity suggests claims could be used to trigger evaluation of neurological events, potentially improving the efficiency of the evaluation of techniques and devices designed to reduce such events.