Hepatic and abdominal adiposity in type 2 diabetes as assessed with machine learning on computed tomography scans

The combined assessment of multiple abdominal imaging traits in relation to type 2 diabetes remains incompletely characterised. The study examines these relationships on computed tomography (CT) scans from a large-scale, racially diverse, disease-focused medical biobank.

Deep learning algorithms were applied to patients with abdominal CT scans in the Penn Medicine BioBank to quantify image-derived phenotypes, including spleen-hepatic attenuation difference (SHAD) for hepatic steatosis (HS), liver and spleen volumes (SV), abdominal visceral and subcutaneous adipose tissue (VAT and SAT, respectively) and visceral-to-subcutaneous ratio (VSR). One thousand five hundred and ninety-four patients (62 years, 49.4% male, 59.3% White), comprising 950 nondiabetics and 644 diabetics, were included in analysis with diabetes status determined by a 6.5% haemoglobin A1c cutoff.

Diabetic patients had greater HS (SHAD -4.49 vs. -6.88 Hounsfield units, p = 1.34 × 10^-8), steatosis prevalence (41.8% vs. 27.7%, p = 4.85 × 10^-9) and VSR (0.62 vs. 0.55, p = 1.69 × 10^-3) than nondiabetics. In multivariate analyses adjusting for age, sex, race and body mass index (BMI), diabetes was independently associated with SHAD (odds ratios [OR] 1.04, 95% confidence interval [1.02-1.05]), SV (OR 4.53 [1.89-10.99]) and VSR (OR 2.87, [1.96-4.20]). Combined regression analysis showed no relationship between splenomegaly and type 2 diabetes once controlling for hepatic factors (OR 1.08, [0.95-1.23]), but uncovered a stronger VSR correlation (OR 1.40, [1.20-1.63]) than BMI (OR 1.14, [1.01-1.29]).

Hepatic steatosis, hepatomegaly and visceral adiposity on CT are associated with type 2 diabetes. Hepatic changes may influence spleen size effects on diabetes. VSR can serve as an alternative to traditional obesity metrics to accurately reflect diabetes risk.