Gastroenterology

Gastroenterology

Volume 129, Issue 1, July 2005, Pages 113-121
Gastroenterology

Clinical-liver, pancreas, and biliary tract
The Natural History of Nonalcoholic Fatty Liver Disease: A Population-Based Cohort Study

https://doi.org/10.1053/j.gastro.2005.04.014Get rights and content

Background & Aims: The natural history of nonalcoholic fatty liver disease (NAFLD) in the community remains unknown. We sought to determine survival and liver-related morbidity among community-based NAFLD patients. Methods: Four hundred twenty patients diagnosed with NAFLD in Olmsted County, Minnesota, between 1980 and 2000 were identified using the resources of the Rochester Epidemiology Project. Medical records were reviewed to confirm diagnosis and determine outcomes up to 2003. Overall survival was compared with the general Minnesota population of the same age and sex. Results: Mean (SD) age at diagnosis was 49 (15) years; 231 (49%) were male. Mean follow-up was 7.6 (4.0) years (range, 0.1–23.5) culminating in 3192 person-years follow-up. Overall, 53 of 420 (12.6%) patients died. Survival was lower than the expected survival for the general population (standardized mortality ratio, 1.34; 95% CI, 1.003–1.76; P = .03). Higher mortality was associated with age (hazard ratio per decade, 2.2; 95% CI, 1.7–2.7), impaired fasting glucose (hazard ratio, 2.6; 95% CI, 1.3–5.2), and cirrhosis (hazard ratio, 3.1, 95% CI, 1.2–7.8). Liver disease was the third leading cause of death (as compared with the thirteenth leading cause of death in the general Minnesota population), occurring in 7 (1.7%) subjects. Twenty-one (5%) patients were diagnosed with cirrhosis, and 13 (3.1%) developed liver-related complications, including 1 requiring transplantation and 2 developing hepatocellular carcinoma. Conclusions: Mortality among community-diagnosed NAFLD patients is higher than the general population and is associated with older age, impaired fasting glucose, and cirrhosis. Liver-related death is a leading cause of mortality, although the absolute risk is low.

Section snippets

Setting

The study population consisted of residents of Olmsted County, located in southeastern Minnesota. According to census data, the total population in the year 2000 was 124,000 people, with 81% of these living in urban areas and the remainder in rural farming areas.15 The proportion of whites in the population was 90.3%, compared with the general US population of 75.1%. The proportion of people with college education was 34.7%, compared with the general US population proportion of 24.4%.

Case Ascertainment

Patients

Patient Population

The 435 patients were predominantly middle-aged whites with an equal sex distribution (Table 1). Of the nonwhite patients, 20 (5%) were Asian, 6 (1%) Arabic, 5 (1%) Hispanic, and 2 (0.5%) African American. Features of metabolic syndrome were common. In particular, obesity was present in over two thirds of the population. IFG (glucose ≥110 mg/dL) was present in 159 (37%) patients, with 112 (26%) of these being diabetic.

The adjusted incidence rate of NAFLD diagnosis increased significantly over

Discussion

This study is the first to describe the natural history of NAFLD in a large cohort of community-based patients. Mortality was significantly increased among patients with NAFLD compared with the expected mortality of the general population of same age and sex and was predicted by presence of IFG/diabetes, cirrhosis, and older age. Death occurred in 12.6% of patients and was most commonly due to malignancy and ischemic heart disease, which are also the 2 most common causes of death in the

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    L.A. was supported by an overseas medical scholarship from the Faculty of Medicine and Dentistry, The University of Western Australia.

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