OBJECTIVES: To identify and characterize the pathways by which patients are diagnosed with non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH).

METHODS: De-identified electronic hospital records were analyzed to identify patients with NAFLD/NASH using the Arcturis UK dataset between 1 January 2015 and 5 April 2024. Patients entered on first NAFLD/NASH diagnosis and were excluded if they had any record for alcoholic liver disease. Pathways to diagnosis were classified into 8 cohorts based on the patient’s entry to hospital in the diagnosing spell (emergency or routine), presence of abnormal liver laboratory values and diagnosis of metabolic conditions of interest in the year prior to diagnosis. Each cohort’s demographic and comorbidity profiles were described, along with their 1-year crude incidence rate of death. Use of 56 different laboratory tests were described in pre-specified windows between 5 years prior to and 1 year after NAFLD/NASH diagnosis.

RESULTS: Of 22,444 patients diagnosed with NAFLD/NASH, 5089 were emergency and 3505 routine entries with abnormal labs and comorbidities, 3504 emergency and 2521 routine entries with abnormal labs, 1837 emergency and 2702 routine entries with comorbidities and 1352 emergency and 1934 routine entries without abnormal labs or comorbidities. Emergency entries with abnormal labs and comorbidities had the highest 1-year incidence of death (2882 per 10,000 person years). In the month prior to diagnosis, patients entering through emergency care were more likely than routine entries to be tested for alkaline phosphatase (54% vs. 19%), alanine transaminase (88% vs. 49%), and bilirubin (88% vs. 51%), and less likely to be tested for gamma-glutamyltransferase (7% vs. 21%).

CONCLUSIONS: We have identified and characterized 8 potential pathways to NAFLD/NASH diagnosis. These pathways can help inform recruitment for clinical trials assessing novel therapies for NAFLD/NASH patients.