B0510 - Nonalcoholic Fatty Liver Disease in Overweight Primary Care Patients: Comparison of Clinical Diagnosis vs Fibrosis-4 and Hepatic Steatosis Index Scores

Introduction: More than two-thirds of US adults are overweight or have obesity, a risk factor for nonalcoholic fatty liver disease (NAFLD). NAFLD is asymptomatic until late in the disease. Therefore, the aim of this study was to assess whether early evidence of NAFLD is being appropriately diagnosed in a primary care patient population.

Methods: A retrospective data analysis was performed of overweight (BMI ≥ 23 for Asians or ≥ 25 for other races) patients (age ≥ 18) who had established primary care (defined as ≥ 2 visits in primary care) in a large healthcare system in Minneapolis between 2010 to 2019. Patients with a diagnosis of alcoholic liver disease, and hepatitis B and C virus infections were excluded. The clinical diagnosis of NAFLD was based on ICD-9 and -10 codes (571.8, K75.81, K76.0). Fibrosis 4 (FIB-4) score ≥ 3.25 and hepatic steatosis index (HSI) score ≥ 36 were calculated as markers of hepatic fibrosis and fatty liver disease, respectively. ICD codes were compared to FIB-4 and HSI scores.

Results: 373,917 patients met study criteria; 52% were female, 86% white, average BMI at first primary care visit was 31.1 (SD 6.0) and average age was 46.4 (SD 17.3). At the end of the follow-up period in 2019, 6.6% of patients met criteria for hepatic fibrosis by FIB-4 score and 90.4% met criteria for fatty liver disease by HSI score. Among patients who met criteria for hepatic fibrosis by FIB-4 score, only 10.7% had been diagnosed as having NAFLD/NASH by ICD code; among those who met criteria for fatty liver disease by HSI criteria, only 6% had been diagnosed by ICD code (Table 1). A formal diagnosis of NAFLD/fatty liver/NASH by ICD code had been made in 4.1% of patients. Out of these patients, 97.7% had fatty liver by HSI score and 11.9% had hepatic fibrosis by FIB-4 score.

Limitations: For 110,994 patients, a FIB-4 or HSI score could not be calculated. Duration of follow up was maximally nine years. Treatment information was not analyzed.

Discussion: Hepatic fibrosis and fatty liver disease are underdiagnosed in this healthcare system based on abnormal FIB-4 and HSI scores. These results are likely generalizable to other healthcare systems in the US. Given the frequency and reversibility of early NAFLD, primary care providers should have a low threshold to screen using simple labs tests (AST, ALT, platelet count) for fatty liver disease and hepatic fibrosis. Those with abnormal results should pursue intensive lifestyle modification and weight loss treatment.