Liver function markers predict cardiovascular and renal outcomes in the CANVAS Program

Background Raised liver function tests (LFTs) have been correlated with multiple metabolic abnormalities and variably associated with cardiorenal outcomes. We sought to systematically test the relationship between LFT levels within the accepted range and major cardiorenal outcomes in a large clinical trial in type 2 diabetes, and the possible impact of placebo-controlled canagliflozin treatment. Methods We measured serum alanine aminotransferase (ALT), aspartic aminotransferase (AST), gamma-glutamyl transferase (γGT), alkaline phosphatase (ALP), and bilirubin concentrations in 10,142 patients, at baseline and repeatedly over follow-up. The relation of LFTs to first hospitalized heart failure (HHF), cardiovascular (CV) and all-cause mortality, and progression of renal impairment was investigated using multivariate proportional-hazards models. Results In univariate association, ALT was reciprocally predictive, and ALP was positively predictive, of all adjudicated outcomes; γGT also was directly associated with CV—but not renal—outcomes. In multivariate models including all 5 LFTs and 19 potential clinical confounders, ALT was independently associated with lower, and γGT with higher, CV outcomes risk. Canagliflozin treatment significantly reduced ALT, AST, and γGT over time. In a fully adjusted model including updated LFT levels and treatment, γGT was independently associated with CV and all-cause mortality, ALP with renal dysfunction progression, and canagliflozin treatment with significant reduction in HHF and renal risk. Conclusions Higher γGT levels are top LFT markers of risk of HHF and death in patients with diabetes and high CV risk, while ALT are protective. Canagliflozin lowers the risk of HHF and renal damage independently of LFTs and potential confounders.