Raised Liver Enzymes in Newly Diagnosed Type 2 Diabetes

Purpose: Non-alcoholic fatty liver disease (NAFLD) is associated with Type 2 diabetes (T2DM) and the metabolic syndrome, and can progress to chronic liver disease. The incidence of NAFLD in patients with newly diagnosed T2DM has not been studied. We examined the incidence of elevated (>35 iu/l) alanine transaminase (ALT), as a surrogate marker for NAFLD, in patients with newly diagnosed T2DM. Methods: All newly diagnosed T2DM patients from the Poole area attend three education sessions at Poole Hospital Diabetes Centre. At the first session, body mass index (BMI) is measured and venous blood taken for glycated haemoglobin (HbA1C), ALT and lipid profile. Results were entered onto a computer database (Proton, CCL Computing, UK). Data was obtained retrospectively. Patients were divided into two groups: those who had ALT within the normal range (ALT≤35 iu/l), and those who had elevated ALT (ALT>35 iu/l.) Power calculations were carried out a priori, with 600 subjects required to allow adequate numbers in each group. Variables with normal distribution (Age, BMI, HbA1c, Total Cholesterol and HDL-Cholesterol) were compared using student t-test, whereas Triglycerides were compared using Mann-Whitney U test, and sex was compared using Chi-squared test. Results: Data was retrieved from 650 consecutive patients who attended the education sessions between June 2004 and April 2005 of whom 44 had incomplete data sets. Data from 606 patients were therefore analysed. ALT was elevated in 155 patients (25.6% (95% CI 22.1, 29.2)), who tended to be older (mean difference 7.3 years (5.2, 9.5), P<0.001), heavier (BMI mean difference 2.0 kg.m-2 (1.0, 3.0), p<0.001), and more likely to be male (M:F raised ALT 104:51, normal ALT 219:232, p<0.001), with higher triglycerides (median difference 0.2 mmol.l-1, p=0.001) and lower HDL cholesterol (mean difference 0.09 mmol.l-1 (0.02, 0.15), p=0.001).There were no statistically significant difference in HBA1C or total cholesterol. Conclusion: Elevated ALT used as a surrogate marker of NAFLD, does suggest that this condition may be common within people with T2DM. In a well defined population of newly diagnosed people with T2DM, there is a high incidence of abnormal ALT levels, which is associated with features of the metabolic syndrome (obesity and lipid abnormalities), but not glycaemic control. Our study suggests that it may be possible to identify people with T2DM who are at higher risk of developing NAFLD. In these individuals attention should be focussed on modification of metabolic risk factors, such as weight loss, treatment of hypertension and control of dyslipidaemia rather than just tighter glycaemic control, thereby potentially preventing significant mortality and morbidity.