Abnormal liver function tests in patients with Type 1 diabetes mellitus: prevalence, clinical correlations and underlying pathologies

Aims To determine the prevalence of elevated alanine transaminase (ALT) in a large cohort of patients with Type 1 diabetes and to examine the clinical correlations and causes. Methods Patients with Type 1 diabetes mellitus were prospectively recruited and ALT, glycated haemoglobin and lipid profile were measured. Patients with Type 2 diabetes mellitus were recruited as a comparison group. Patients with abnormal ALT were investigated for underlying causes. Prevalence of abnormal ALT was analysed at three separate cut-offs and multivariable analysis used to identify independent risk factors. Results Nine hundred and eleven with Type 1 diabetes and 963 with Type 2 diabetes were included. The prevalence of elevated ALT was dependent on the cut-off value: > 30 IU/l in males and > 19 IU/l in females, > 50 and > 63 IU/l was 34.5, 4.3 and 1.9%, respectively, in Type 1 diabetes and 51.4, 8.2 and 3.7%, respectively, in Type 2 diabetes. In Type 1 diabetes an elevated ALT was associated with worse glycaemic control, age > 55 years and elevated triglycerides. Investigation of these patients revealed a cause in 43.6% of patients, predominantly non-alcoholic fatty liver disease (NAFLD). Conclusions Elevated ALT is not uncommon in Type 1 diabetes and is associated with NAFLD-related risk factors. Patients with Type 1 diabetes and elevated ALT should be investigated as significant abnormalities may be found which are amenable to interventions.