In Cox proportional hazard regression analysis, upper tertile ALT and GGT were associated with increased risk of CAN (ALT: hazard ratio [HR] 1.52, 95% CI [1.12, 2.07] and GGT 1.60 [1.17, 2.19], respectively), independent of HbA1c and diabetes duration (Figure 2). Here, GPT is linked to diabetes mellitus.