Elevated serum alanine transaminase in patients with type 1 or type 2 diabetes mellitus.
BACKGROUND
The risk of chronic liver disease is higher in diabetics, and serum alanine transaminase (ALT) is a sensitive predictor of mortality from liver disease.


AIM
To estimate the prevalence of elevated ALT in type 1 and type 2 diabetes, and identify possible risk factors.


METHODS
We identified all patients (n = 2077) attending review between September 2002 and August 2003. We excluded those with no ALT measurement (n = 73); those whose alcohol consumption was >14 units/week (women) (n = 276) or >21 units/week (men) (n = 324); and those with a diagnosis of Maturity Onset Diabetes of the Young, secondary diabetes, gestational diabetes or uncertain type of diabetes (n = 51). We calculated the prevalences of elevated ALT in both type 1 and type 2 diabetes patients, and compared the demographic, microvascular risk factors and current drug use between each group using multivariate logistic regression.


RESULTS
Of 1353 patients included, 836 (61.9%) had type 2 diabetes. Elevated ALT was found in 9.5% (95%CI 7.1-12.3%) of patients with type 1 diabetes, and 12.1% (95%CI 9.9-14.5%) of those with type 2 diabetes. The risk of elevated ALT in patients with type 2 diabetes increased with increasing body mass index (p(trend) = 0.04), and was lower in those taking insulin (OR 0.38, 95%CI 0.22-0.65).


DISCUSSION
The prevalence of elevated ALT is 3-4 times higher in patients with either type 1 or type 2 diabetes than in the general population. Further studies investigating the aetiology and mechanisms of this elevation may suggest appropriate early interventions.