Context and objective: NAFLD, and its more severe form with steatohepatitis (NASH), are common in patients with T2DM. However, they are usually believed to affect largely those with elevated aminotransferases. The aim of this study was to determine the prevalence of NAFLD (by the gold-standard liver magnetic resonance and spectroscopy or (1)H-MRS) in patients with T2DM and normal aminotransferases, and to characterize their metabolic profile.
Participants and methods: We recruited 103 patients with T2DM and normal plasma aminotransferases (age: 60±8 years, BMI: 33±5 kg/m(2), A1c: 7.6±1.3%). We measured: i) liver triglyceride content by (1)H-MRS; ii) systemic insulin sensitivity (HOMA-IR), and iii) adipose tissue insulin resistance (IR), both fasting (as the adipose tissue IR index: fasting plasma FFA x insulin) and during an OGTT (as the suppression of FFA).
Results: The prevalence of NAFLD and NASH were much higher than expected (76% and 56%, respectively). The prevalence of NAFLD was higher in obese compared to non-obese patients, as well as with increasing BMI (p=0.03 for trend). Higher plasma A1c was associated with a greater prevalence of NAFLD and worse liver triglyceride accumulation (p<0.01). Compared to non-obese patients without NAFLD, patients with NAFLD had severe systemic (liver/muscle), and particularly, adipose tissue (fasting/postprandial) insulin resistance (all p<0.01).
Conclusions: The prevalence of NAFLD is much higher than previously believed in overweight/obese patients with T2DM and normal aminotransferases. Moreover, many are at increased risk of severe liver disease (NASH). Physicians should have a lower threshold for screening patients with T2DM for NAFLD/NASH.