OBJECTIVES: To estimate the prevalence and describe the clinical characteristics of the coded NASH and coded cirrhotic NASH populations in the US after NASH and cirrhosis-specific ICD10 (International Classification of Disease 10th Revision, Clinical Modification ICD-10-CM) codes were introduced.

METHODS: An observational retrospective cohort study was conducted using the Forian US integrated medical claims database. Identification of NASH cases were based on an ever-coded definition and included patients (all ages) with ≥1 NASH ICD10 (K75.81) coded diagnosis during the identification period (01JAN2015-31DEC2020; index=first NASH code date). For NASH subgroups, fibrosis stage was estimated using standard FIB-4: <1.3 (F0/1) and >2.67 (F3); subgroups of newly-coded versus recurrent-coded patients (multiyear) were also identified. A second cohort analysis was conducted based on ever-coded definition including patients (all ages) with ≥1 NASH ICD10 plus ≥1 cirrhosis code (ICD10: K75.81+[K7030, K7031, K7469, K7460, P7881, K741, K717, K742]). The two cohorts were compared to estimate non-cirrhotic NASH. Annual descriptive statistics for each cohort were calculated and scaled using the years known database sample size to estimate the coded US prevalence.

RESULTS: Overall (mean age; male), 611,495 (59 years;43%) patients had ≥1 NASH diagnosis and 189,074 had ≥1 NASH plus cirrhosis diagnosis. Estimated non-cirrhotic NASH: 422,421. Overall NASH cohort, most common comorbidities (N;%): hypertension (443,311;72%), dyslipidemia (379,920;62%), obesity (327,776;54%). NASH cohort subgroup, FIB-4 (3% of NASH cohort): F0/F1 (26%), F2/F3 (35%), F4 (39%). NASH cohort subgroup, annual newly coded (recurrent): 37,338 (37,338), 114,656 (132,424), 116,119 (165,644), 116,732 (188,192), 118,623 (206,277), 108,027 (202,721) for 2015, 2016, 2017, 2018, 2019, 2020, respectively. The 2020 US prevalence estimate for diagnosed/ever-coded NASH was 952,001; approximately 10% of NASH prevalence estimates reported in the literature.

CONCLUSIONS: Using US claims from 2015-2020, there were 611,495 patients ever coded for NASH and 189,074 ever coded for cirrhotic NASH after the 2015 introduction of the NASH ICD10 code.