Incidence and causes of mildly to moderately elevated aminotransferase in Japanese patients with type 2 diabetes

Objectives To identify the association of type 2 diabetes (T2DM) and liver disease with elevated ALT and factors associated with increased ALT in patients with and without T2DM. Design and setting We performed a retrospective study in adults with >= 2 claims for blood tests recorded in the Medical Data Vision claims database between 2010 and 2016. Participants Patients were entered into T2DM and non-DM groups based on diagnosis and medication claim codes. Primary outcome measure The primary endpoint was the first follow-up ALT elevation over three times the normal value, and etiologies were categorized by subsequent diagnoses. We estimated the ALT elevation incidence and association with T2DM using Poisson regression and Cox proportional hazard models. Results We identified 3161 cases of elevated ALT in 104,903 patients (follow-up, 280,659 patient-years). The age- and sex-adjusted incidence of elevated ALT in the T2DM group (13.47 per 1000 patient-years; 95% confidence interval (CI) 12.53-14.48) was significantly higher than that in the non-DM group (8.43 per 1000 patient-years; 95% CI 7.72-9.20, p < 0.0001). Compared to the non-DM group, the T2DM group had an approximately 3.5 times higher risk of fatty liver-related ALT elevation (adjusted hazard ratio (HR), 3.54; 95% CI 1.90-6.58). T2DM was not associated with an increased incidence of jointly elevated ALT and total bilirubin (adjusted HR, 0.94; 95% CI 0.77-1.15). Conclusion T2DM is strongly associated with increased liver enzymes secondary to fatty liver. The causes of liver enzyme abnormalities were not fully characterized due to a high proportion of unexplained ALT elevation.