Background
In the previous study, we found that pancreatic steatosis was associated with subclinical atherosclerosis in patients with type 2 diabetes mellitus. This finding suggests that pancreatic steatosis might be related to macrovascular complication.

Aim
We hypothesized that pancreatic steatosis could also effect to microvascular complication. So, we investigated whether pancreatic steatosis was associated with diabetic retinopathy and nephropathy in patients with type 2 diabetes mellitus.

Method
Total one hundred eighty-six consecutive patients with type 2 diabetes mellitus in whom conventional outpatient treatment with either diet or any combination of oral antidiabetic agents had failed were referred to the inpatient diabetes service. Computed tomography (CT) images were acquired using the standard clinical abdominal CT protocol utilizing a multi-slice CT scanner. Pancreatic CT attenuations was measured in three pancreatic regions (head, body and tail) with areas of 1.0cm². Obesity was defined as body mass index (BMI) ≥ 25 kg/m² according to the Asian-specific BMI cut-off values from the World Health Organization report. The presence of diabetic retinopathy was assessed by an expert ophthalmologist using dilated fundoscopy. Diabetic nephropathy was assessed by albumin-creatine ratio (ACR, mcg/mg) using spot urine. For assessment of pancreatic steatosis, we used three parameters. First was mean pancreatic CT attenuation (P-mean) of three pancreatic regions (head, body and tail). Second was difference between mean pancreatic to splenic attenuation (P-S), Third was ratio of pancreas-to-spleen attenuation (P/S). All parameters was expressed as Hounsfield unit.

Results
The mean duration of diabetes was 14.9±9.55 years and mean age was 58.29 ± 14.7 years. The mean BMI was 25.9±4.1 kg/m2 and mean HbA1c was 9.57 ± 2.09%. All pancreatic steatosis parameters were negatively correlated with age (r= -0.293, P<0.0001), duration of diabetes (r=-0.233, P=0.0025), waist circumference (r=-0.291, P=0.0001), total abdominal fat area (r=-0.239, P=0.0007), and visceral fat area (r= -0.206, P=0.0038). All pancreatic steatosis parameters were significantly associated with diabetic retinopathy and nephropathy P-mean had an odd ratio (OR) of 2.205 (95% CI, 1.217–3.995), P-S had an OR of 1.909 (95% CI, 1.058 – 3.444), and P/S had an OR of 2.173 (95% CI, 1.201-3.933) for retinopathy. For nephropathy defined as ACR > 30, P-mean had an odd ratio (OR) of 2.143 (95% CI, 1.173–3.918), P-S had an OR of 2.021 (95% CI, 1.108 – 3.687), and P/S had an OR of 2.095 (95% CI, 1.148-3.825). 

Discussion
In this study, pancreatic steatosis was significantly associated with diabetic retinopathy and nephropathy in subjects with type 2 diabetes mellitus. This result suggests that pancreatic steatosis has close relationship with diabetic microvascular complications. Further study will be needed to clarify the mechanism and causal-relationship of pancreatic steatosis in the development of microvascular complications in diabetes mellitus.

Association between pancreatic steatosis and diabetic microvascular complications in type 2 diabetes mellitus