Article Title

ICD-10: A Transition That’s Already Happening

Publication Date



ICD-10, electronic health record


Background/Aims: The United States currently uses ICD version 9 (ICD-9) for diagnosis and procedure coding. Federal regulations require that U.S. health care providers adopt the next version (ICD-10) by 10/1/2015. The new version expands the number of diagnosis codes from about 13,000 to 68,000, and increases the number of procedure codes from approximately 4,000 to 90,000. The Centers for Medicare & Medicaid Services delayed its ICD-10 implementation date from 10/1/2014 to 10/1/2015 as a result of congressional action. However, changes to the electronic health records based on ICD-10 have continued to move forward. These changes include changing the pick lists that providers choose from as well as revamping the underlying data structures to support diagnoses coding.

Methods: The Center for Health Research Kaiser Northwest ICD-10 remediation team worked with research project staff to develop a set of diagnosis groupings (e.g. diabetes, renal disease, dementia, etc.) that can be coded under both ICD-9 and ICD-10. The team mapped the expanded provider selections to both ICD-9 and ICD-10. The team then developed a set of monitoring reports for these diagnosis groupings in order to look for points of discontinuity between ICD-9 and ICD-10.

Results: We found variation in rates of diagnosis groupings before and after the change to provider pick lists. Most diagnoses groupings have not shown a substantial change from the transition to more granularly defined diagnosis pick lists. However, when bilateral diagnosis codes are used, there can be irregularities in diagnosis rates.

Discussion: Preparing for ICD-10 has generated multiple changes to the electronic health record systems and their underlying data structures. Research projects should explore whether these changes are already impacting diagnoses and procedure-coding rates. In particular, research projects should look at trends in diagnoses rates when bilateral diagnosis codes are used.




April 2nd, 2015


April 28th, 2015