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Obesity correlates with discordance in noninvasive tests for fibrosis
Compared with biopsy results for fibrosis, BMI in the obesity range correlated with discordance between magnetic resonance elastography and transient elastography among patients with nonalcoholic fatty liver disease, according to recently published data. Further, discordance increased proportional with increased BMI.
“We are trying to see when vibration-controlled transient elastography can provide a reading that would be concordant with MRE so in those circumstances we can just use vibration-controlled transient elastography — a cheaper test — and then utilize MRE in cases when vibration-controlled transient elastography is not likely to be concordant with MRE,” Rohit Loomba, MD, MHSc, director of the NAFLD Research Center, UC San Diego Health, and professor of medicine at UC San Diego School of Medicine, told Healio.com/Hepatology. “This study tries to tease that out to help the clinician and also move the field forward towards an integrated approach of using various imaging modalities for the assessment of fibrosis in NAFLD.”
From October 2011 to January 2017, the researchers enrolled 119 patients with suspected NAFLD who underwent contemporaneous MRE, transient elastography (TE) and liver biopsy. Mean patient age was 49.8 years, 54.6% of patients were women, and mean BMI was 30.6 kg/m2.
Additionally, the researchers enrolled 75 patients with obesity and biopsy-proven NAFLD from the Mayo Clinic NAFLD Cohort as a validation group. Mean patient age was 47.68 years, 66.7% were women, and mean BMI was 41.7 kg/m2.
The rate of discordance between MRE and TE for significant fibrosis (stage 2 to 4 vs. stage 0 to 1) was 43.7% among the initial cohort and 45.3% among the Mayo Clinic validation cohort.
In the initial cohort, BMI correlated significantly with discordance between MRE and TE for the stage of significant liver fibrosis after both univariate analysis (OR = 1.626; 95% CI, 1.116-2.37) and multivariate analysis (OR = 1.694; 95% CI, 1.145-2.507). Discordance increased as BMI increased (P = .0309) and was significantly higher in patients with BMI of 35 kg/m2 or higher compared with those with lower BMI (63% vs. 38%; P = .022).
In the validation cohort, BMI was also a significant predictor of discordancy between MRE and TE for the stage of significant liver fibrosis after univariate analysis (OR = 1.469; 95% CI, 1.019-2.116) and multivariable analysis (OR = 1.52; 95% CI, 1.044-2.213). Like the initial cohort, discordance increased as BMI increased (P = .0011) and was higher among patients considered morbidly obese compared with those with lower BMI (66% vs. 35.7%; P = .001).
“This study showed that the grade of obesity is also a significant predictor of discordancy between MRE and TE as the discordance-rate between MRE and TE increases with the increase in BMI,” the researchers concluded. “Further cost-effectiveness studies are needed to determine the optimal approach for the detection of liver fibrosis taking into account the higher risk of liver fibrosis and the higher discordance-rate when the BMI increases.” – by Talitha Bennett
Disclosure: Caussy reports no relevant financial disclosures. Please see the full study for the other researchers’ relevant financial disclosures.