Abstract
This dataset contains information on the 443 of 451 patients who had bariatric surgery at the Cleveland Clinic between 2005 and 2009 and underwent livery biopsy. These data are from Wu et al (2012), who conducted a retrospective cohort study to estimate the prevalence of liver steatosis (fatty liver disease) and fibrosis in these patients and to determine the suitability of ultrasound for diagnosing liver steatosis. Two prevalence outcomes were investigated, liver steatosis and fibrosis. Liver steatosis was diagnosed independently using both a liver biopsy (gold standard) and ultrasound. Fibrosis was diagnosed by inspection of the biopsy specimen. Covariate information is also available and includes demographics, comorbidities, and clinical characteristics. Statistical analysis included estimating the 95% confidence interval for prevalence, assessment of the overall diagnostic performance of ultrasound for detecting liver steatosis (accuracy, sensitivity, specificity, predictive value positive, predictive value negative) and multiple predictor logistic regression to explore how the performance of ultrasound for detecting liver steatosis varied by the covariates of interest. Wu et al. (2012) estimated that approximately three quarters of bariatric surgery patients have liver steatosis, and approximately one quarter have fibrosis. Ultrasound was only moderately diagnostic for liver steatosis but was sufficient for clinical use in patients with a severity of fatty liver disease NAS score ≥2 and in patients for whom the duration of obesity was greater than 30 years.
| Study Design | Topic | Statistical Method | Statistical Method | Statistical Method |
|---|---|---|---|---|
| Retrospective Cohort | Liver Steatosis | Description | Diagnostic Screening | Logistic Regression |
Contributor
The liver steatosis dataset was contributed by Dr. Amy Nowacki, Associate Professor, Cleveland Clinic. Please refer to this resource as: Amy S. Nowacki, “Liver Steatosis Dataset”, TSHS Resources Portal (2025). Available at https://www.causeweb.org/tshs/liver-steatosis/.
Background
The prevalence of morbid obesity is rising and is often accompanied by liver steatosis. Liver steatosis, defined as fat accumulation exceeding 5% of normal liver wet weight, is a chronic disorder with both alcoholic and nonalcoholic etiologies. The progressive form of the disease, steatohepatitis, can progress to fibrosis, cirrhosis, and eventually to end-stage liver disease and hepatocellular carcinoma. Diagnosing liver steatosis and fibrosis in morbidly obese subjects by liver biopsy, while the “gold standard”, is invasive and not without risk, thus rendering the utility of this diagnostic tool unclear.
Ultrasound for the detection of liver steatosis is an attractive alternative to liver biopsy. It is well established that ultrasound can detect uniform fatty infiltration of liver and, additionally, is inexpensive, safe, and well tolerated by patients. However, the quality of ultrasonic images is presumably degraded in morbidly obese patients due to thickening of the abdominal wall, thus reducing diagnostic accuracy. As well, clinical characteristics might also influence the diagnostic value of ultrasound for steatosis.
Objective
The study objectives were to determine the prevalence of liver steatosis and fibrosis in patients undergoing bariatric surgery using liver biopsy and to determine the suitability of ultrasound for diagnosing liver steatosis with and without simultaneously considering patient characteristics.
Subjects & Variables
| Subject | # Obs | # Var | Introduction | Data Dictionary |
|---|---|---|---|---|
| Liver Steatosis | 443 | 22 | Liver Steatosis Dataset Introduction | Liver Steatosis Data Dictionary |
Data Downloads
| Posting Date | Contributor (email) |
|---|---|
| 8/1/25 | Amy S. Nowacki (nowacka@ccf.org) |
| R | SAS | STATA | SPSS | Minitab | Excel |
|---|---|---|---|---|---|
| Liver Steatosis-R | Liver Steatosis-SAS | Liver Steatosis-Stata | Liver Steatosis-SPSS | Liver Steatosis-Minitab | Liver Steatosis-Excel |
Teaching Resources
last updated on 8/1/2025
| # | Name (link) | Posting Date | Author (email) | Type | Statistical Topic | Level | Keywords |
|---|---|---|---|---|---|---|---|
| – | – | – | – | – | – | – | – |