The epidemiology of newly diagnosed chronic liver disease in gastroenterology practices in the United States: results from population-based surveillance.

OBJECTIVES: Chronic liver disease (CLD) is an important cause of morbidity and mortality, but the epidemiology is not well described. We conducted prospective population-based surveillance to estimate newly diagnosed CLD incidence, characterize etiology distribution, and determine disease stage.

METHODS: We identified cases of CLD newly diagnosed during 1999-2001 among adult county residents seen in any gastroenterology practice in New Haven County, Connecticut; Multnomah County, Oregon; and Northern California Kaiser Permanente Medical Care Program (KPMCP, Oakland, California [total population 1.48 million]). We defined CLD as abnormal liver tests of at least 6 months' duration or pathologic, clinical, or radiologic evidence of CLD. Consenting patients were interviewed, a blood specimen obtained, and the medical record reviewed.

RESULTS: We identified 2,353 patients with newly diagnosed CLD (63.9 cases/100,000 population), including 1,225 hepatitis C patients (33.2 cases/100,000). Men aged 45-54 yr had the highest hepatitis C incidence rate (111.3/100,000). Among 1,040 enrolled patients, the median age was 48 yr (range 19-86 yr). Hepatitis C, either alone (442 [42%]) or in combination with alcohol-related liver disease (ALD) (228 [22%]), accounted for two-thirds of the cases. Other etiologies included nonalcoholic fatty liver disease (NAFLD, 95 [9%]), ALD (82 [8%]), and hepatitis B (36 [3%]). Other identified etiologies each accounted for <3% of the cases. A total of 184 patients (18%) presented with cirrhosis, including 44% of patients with ALD.

CONCLUSIONS: Extrapolating from this population-based surveillance network to the adult U.S. population, approximately 150,000 patients with CLD were diagnosed in gastroenterology practices each year during 1999-2001. Most patients had hepatitis C; heavy alcohol consumption among these patients was common. Almost 20% of patients, an estimated 30,000 per year, had cirrhosis at presentation. These results provide population-level baseline data to evaluate trends in identification of patients with CLD in gastroenterology practices.