Details
In this report, we compare the frequency of diagnosis codes for Crohn's disease to examine trends in code usage surrounding the October 2015 transition from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) to International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes. We determined mappings by performing comprehensive code list searches in both the ICD-9 and ICD-10 eras and leveraging the Centers for Medicare and Medicaid Services (CMS) General Equivalence Mappings (GEMs). We used forward-backward mapping as part of this comprehensive approach.¹
¹Fung, K. W., et al. (2016). "Preparing for the ICD-10-CM Transition: Automated Methods for Translating ICD Codes in Clinical Phenotype Definitions." EGEMS (Wash DC) 4(1): 1211.