What is the incidence and significance of incidental findings of fatty liver on ultrasound of patients followed for nephrolithiasis?
David Bouhadana1, David-Dan Nguyen1, Philip Wong2, Sero Andonian3.
1Faculty of Medicine and Health Sciences, McGill University, Montreal, QC, Canada; 2Division of Gastroenterology & Hepatology, Department of Medicine, McGill University Health Centre, Montreal, QC, Canada; 3Division of Urology, Department of Surgery, McGill University Health Centre, Montreal, QC, Canada
Introduction: Non-alcoholic fatty liver disease (NAFLD) is often diagnosed incidentally on imaging reports when surveying for renal stones. The incidence and implications of these findings on ultrasound reports of kidney stone patients are unknown. Considering that delayed management of significant hepatic steatosis can lead to progression and poor outcomes, we sought to determine the incidence and predictors of incidental ultrasound findings of hepatic steatosis and characterize the management of these patients.
Methods: The medical records of 318 consecutive nephrolithiasis patients between January and February 2018 were retrospectively reviewed. Patients with no previous liver disease, 35 years of age or older, and with available ultrasound imaging were included. Ultrasound reports were reviewed for any incidental finding of hepatic steatosis and the degree of steatosis. Patient demographic predictors of incidental hepatic steatosis were identified using univariable logistic regression models.
Results: One-hundred-sixty-two patients met the inclusion criteria, of which 76 (46.9%) had a finding of hepatic steatosis of any severity and 22 (13.6%) of moderate-to-severe severity. Predictors of finding incidental hepatic steatosis included a higher body mass index (BMI) (odds ratio [OR] 1.2, 95% confidence interval [CI] 1.1–1.2, p<0.001) and smoking (OR 2.6, 95% CI 1.4 –5.1, p=0.004). Of the patients with any-severity incidental finding of hepatic steatosis, steatosis progression was noted for 13 (17.1%) and regression was noted for two (2.6%). Twelve patients were referred to hepatology for further liver investigations. Among these patients, one (8.3%) had cirrhosis, two (16.7%) had fibrosis, and two (16.7%) had moderate-to-severe steatosis.
Conclusions: The incidental finding of fatty liver on ultrasound of patients followed for nephrolithiasis is common, especially in overweight or smoker patients. While only a small proportion of these patients have significant fibroscan-confirmed fibrosis or cirrhosis, urologists could initiate lifestyle changes that improve outcomes for both liver and kidney stone diseases and refer to gastroenterology/hepatology when appropriate.
