ICD-10-CA/CCI coding algorithms for defining clinical variables to assess outcome after aortic and mitral valve...

Implementation of the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Canada (ICD-10-CA) and the Canadian Classification of Interventions (CCI) coding system presents challenges for using Canadian administrative data. Thus, a multi-step process was conducted to develop ICD-10-CA/CCI coding algorithms to define nine comorbidities and three procedures. These clinical variables have been used in ICD-9-CM data for risk adjustment in assessment of outcomes after aortic and mitral valve replacement surgery. Among patients included in the ICD-9-CM data during 1999 and 2001 and in the ICD-10-CA/CCI data during 2002 and 2003 in a Canadian Health Region, frequencies of the nine comorbidities and the three procedures remained generally similar across databases. The newly developed ICD-10-CA/CCI and previous ICD-9-CM coding algorithms are comparable in detecting these clinical variables. However, performance of ICD-10-CA/CCI coding algorithms in risk adjustment should be evaluated in a larger database.