EFFECT OF ICD-10 TRANSITION ON PATIENT IDENTIFICATION AFTER ONE YEAR IN A US MANAGED CARE DATABASE

• Published in: Value in health 2017-05, Vol.20 (5), p.A310
• Main Authors: Hull, M, Blauer-Peterson, C, Seare, J, Chastek, B, Brekke, L
• Format: Article
• Language: English
• Subjects: Arteriosclerosis; Asthma; Atherosclerosis; Cardiovascular diseases; Chronic asthma; Chronic obstructive pulmonary disease; Diabetes mellitus; Diabetes mellitus (non-insulin dependent); Heart diseases; Heart failure; Hepatitis C; Lung cancer; Lung diseases; Managed care; Medical databases; Medical diagnosis; Medicare; Mental depression; Obstructive lung disease; Rheumatoid arthritis; Type 2 diabetes mellitus
• ISSN: 1098-3015; 1524-4733
• DOI: 10.1016/j.jval.2017.05.005

OBJECTIVES: The transition from ICD-9-CM to ICD-10-CM in October 2015 raised potential concerns due to differences in diagnosis code specificity across some conditions. Counts and percentages of patients with each of nine conditions in September 2015, October 2015, and October 2016 were compared in a large US managed care database. METHODS: This retrospective analysis used medical claims data for commercial and Medicare Advantage enrollees in September 2015, October 2015, and October 2016. Patients with > 1 medical claim for type 2 diabetes mellitus (T2DM), depression, lung cancer, rheumatoid arthritis (RA), atherosclerotic cardiovascular disease (ASCVD), chronic obstructive pulmonary disease (COPD), hepatitis C, asthma, or heart failure were retained. ICD-9-CM and ICD-10-CM code lists were constructed by an MD coding specialist. Monthly patient counts for each condition were determined and the percentage of patients with each condition was calculated relative to the entire database. RESULTS: In 2015 and 2016, data were available for 12.45 million and 13.84 million patients, respectively. For 6 of the 9 conditions, the absolute percentage of patients increased after one year (September 2015, October 2015, October 2016): T2DM, 3.15%, 3.11%, 3.47%; depression, 2.00%, 1.86%, 1.89%; lung cancer, 0.11%, 0.11%, 0.12%; RA, 0.26%, 0.26%, 0.27%; ASCVD, 1.18%, 1.68%, 1.84%; COPD, 1.13%, 1.15%, 1.30%; hepatitis C, 0.08%, 0.08%, 0.07%; asthma, 0.87%, 0.82%, 0.85%; heart failure, 0.57%, 0.58%, 0.66%. Possible reasons for these variations included differences in code representations and the use of generalized codes early in the transition. CONCLUSIONS: In this large US managed care database analysis, the transition from ICD-9-CM to ICD-10-CM codes was associated with absolute percentage increases in 6 of 9 conditions after one year, requiring further analysis of the reasons for these increases. These findings indicate the importance of careful review of code lists for analyses bridging the transition period and the need for investigation of the reasons for inconsistencies.