International classification of diseases and current procedural terminology codes underestimated thrombolytic use for ischemic stroke

Abstract

Background and Objective To determine the accuracy of recently introduced International Classification of Diseases Ninth Revision (ICD-9) procedure and Current Procedural Terminology (CPT) codes designed for injection or infusion of thrombolytic agents. Materials and Methods We determined the accuracy of ICD-9 procedure code 99.10 and CPT codes 37201, 37202 for use of thrombolysis in ischemic stroke by comparing procedure codes of University Hospital discharge data with a concurrent prospective registry. Results Of the 369 ischemic stroke patients, 49 (13.3%) received either intravenous and/or intraarterial thrombolysis. The sensitivity and specificity for ICD-9 procedure code 99.10 was 55% and 98% and CPT procedure code 37201 and 37202 was 49% and 99%. Identification by either ICD-9 codes or CPT codes yielded a high sensitivity and specificity of 82% and 98%. Conclusions The use of ICD-9 and CPT codes alone may underestimate the use of thrombolytics using national and regional database. Best results are achieved when a combination of ICD-9 and CPT codes are used to identify the use of thrombolytics.