OBJECTIVES: Nonalcoholic steatohepatitis (NASH) is underdiagnosed and imposes a substantial burden on patients, providers, and payers. This study aimed to measure the impact of risk factors and create a predictive risk score of NASH that can help the management of the disease and increase the likelihood of early diagnoses.

METHODS: Adult patients from U.S. Department of Defense (DoD) data aged ≥18 years with their first diagnosis for NASH were included (Jan. 2020-Oct. 2022). For the NASH cohort, the first NASH diagnosis date was designated as the index date. The inclusion criteria were ≥1 diagnosis of NASH during identification period and age ≥18 years old. A control cohort was generated for patients without NASH, and a random index date within the identification period was selected for controls. One year prior to the index date was selected as a baseline to measure risk factors. Patients with non-alcoholic fatty liver disease and cirrhosis were excluded. Logistic regression was used to assess the odds of NASH, controlling for patient demographics (age, sex, geographic region) and other clinical factors.

RESULTS: We identified 10,551 NASH and 6,413,061 non-NASH patients; mean age was 61.28 years for NASH and 55.84 years for non-NASH patients (p<0.0001). A majority (56.87%) of patients were female. NASH-related baseline comorbidities such as hypertension (48.85% vs. 21.90%) and type 2 diabetes (39.16% vs. 10.50%) were significantly higher in the NASH cohort. Logistic regression showed that male sex (odds ratio [OR]=0.83, 95% confidence interval [CI]=0.80-0.86), increased age (OR=1.99, 95% CI=1.85-2.14 for ages 46-54; OR=2.04, 95% CI=1.91-2.18 for ages 55-64; reference: age 18-45), baseline abnormal AST/ALT (OR=4.46, 95% CI=3.91-5.10), and abnormal liver tests (OR=10.01, 95% CI=9.29-10.79) were positively associated with the risk of NASH among other factors.

CONCLUSIONS: In the U.S. DoD population, abnormal AST/ALT and abnormal liver results were two primary predictors of NASH.