Nonalcoholic fatty liver disease (NAFLD) without insulin resistance: Is it different?

Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of insulin resistance [IR]. However, a significant proportion of NAFLD patients are devoid of IR. Is NAFLD sans IR a different entity? The aim of the study was to compare the anthropometric, metabolic, biochemical, ultrasonography, and histological profile of NAFLD patients with and without IR.

Retrospective analyses of 336 NAFLD patients diagnosed during the last two years was done. Patients without IR were compared with those with IR.

Out of 336 patients, 153 [45.53%] were without IR. Although age, gender, BMI and transaminase levels were comparable, significantly higher proportion of patients in non-IR group were non-obese [43.14% vs. 25/14%; P=0.0005], and had mild fatty change on ultrasonography; [78.43% vs. 67.21%; P=0.022]. Higher proportion of them had elevated transaminases; [67.97% vs. 56.83%; P=0.036]. Serum triglyceride [178.52±78.78 vs. 204.86±94.72 mg/dl; P=0.02], FBG [85.39±13.80 vs. 98.93±31.56 mg/dl; P=0.00], PGBG [123.76±36.77 vs. 148.07±64.67m g/dl; P=0.00], and serum insulin [6.33±2.18 vs. 15.39±12.56 μIU/ml; P=0.00] were significantly lower in patients without IR. Although there was no difference in histology, interestingly fibrosis was seen in one third of patients despite absence of IR.

Nearly half of our NAFLD population was without IR; one third of them had significant fibrosis. NAFLD is probably a heterogeneous disease and IR is not the sole factor responsible for NAFLD; further studies are needed to find out other possible etiological factors.