Impact of Type 2 Diabetes on the Accuracy of Noninvasive Tests of Liver Fibrosis With Resulting Clinical Implications

Background & Aims Noninvasive tests (NITs) of liver fibrosis have been suggested to be less accurate in type 2 diabetes mellitus (T2DM). We aimed to compare the accuracy of 6 NITs between patients with or without T2DM, explain any differences, and adapt diagnostic algorithms for clinical practice accordingly. Methods We included 1051 patients with nonalcoholic fatty liver disease with liver biopsy, blood fibrosis tests (Nonalcoholic Fatty Liver Disease Fibrosis Score, FIB4, Fibrotest, FibroMeter), vibration-controlled transient elastography (VCTE), and the combinatory elasto-blood test FibroMeterVCTE. The study endpoint was advanced fibrosis on liver biopsy. Results NIT areas under the receiver operating characteristic curve were significantly lower in patients with T2DM, mostly because of a decrease in specificity. For FIB4, this decrease in specificity was only related to the higher age of patients with T2DM enrolled. For Fibrotest, FibroMeter, and FibroMeterVCTE, the decrease in specificity was related to age but also to higher alpha2-macroglobulin level, which is known to increase in T2DM. Sensitivity was unaffected by T2DM, but it masked a doubled raw number of false negatives because of the 2-fold higher prevalence of advanced fibrosis in that setting. The sequential algorithm FIB4-vibration-controlled transient elastography had 90.3% accuracy in patients without T2DM vs 79.0% in those with (P < .001). Algorithms using first-line specialized tests maintained a low rate of false negatives and false positives in T2DM. Conclusions The decrease in NIT accuracy observed in T2DM is partly biased by the different characteristics of the groups studied, but also linked to T2DM itself through modification of the levels of some NIT biomarkers. Specialized tests should be used first-line to diagnose advanced liver fibrosis in T2DM. Noninvasive tests (NITs) of liver fibrosis have been suggested to be less accurate in type 2 diabetes mellitus (T2DM). We aimed to compare the accuracy of 6 NITs between patients with or without T2DM, explain any differences, and adapt diagnostic algorithms for clinical practice accordingly. We included 1051 patients with nonalcoholic fatty liver disease with liver biopsy, blood fibrosis tests (Nonalcoholic Fatty Liver Disease Fibrosis Score, FIB4, Fibrotest, FibroMeter), vibration-controlled transient elastography (VCTE), and the combinatory elasto-blood test FibroMeterVCTE. The study endpoint was advanced fibrosis on liver biopsy. NIT areas under the receiver operating characteristic curve were significantly lower in patients with T2DM, mostly because of a decrease in specificity. For FIB4, this decrease in specificity was only related to the higher age of patients with T2DM enrolled. For Fibrotest, FibroMeter, and FibroMeterVCTE, the decrease in specificity was related to age but also to higher alpha2-macroglobulin level, which is known to increase in T2DM. Sensitivity was unaffected by T2DM, but it masked a doubled raw number of false negatives because of the 2-fold higher prevalence of advanced fibrosis in that setting. The sequential algorithm FIB4-vibration-controlled transient elastography had 90.3% accuracy in patients without T2DM vs 79.0% in those with (P < .001). Algorithms using first-line specialized tests maintained a low rate of false negatives and false positives in T2DM. The decrease in NIT accuracy observed in T2DM is partly biased by the different characteristics of the groups studied, but also linked to T2DM itself through modification of the levels of some NIT biomarkers. Specialized tests should be used first-line to diagnose advanced liver fibrosis in T2DM.