Circulating amino acids and the risk of macrovascular, microvascular and mortality outcomes in individuals with type 2 diabetes: results from the ADVANCE trial

Abstract

Aims/hypotheses: We aimed to quantify the association of individual circulating amino acids with macrovascular disease, microvascular disease and all-cause mortality in individuals with type 2 diabetes.

Methods: We performed a case-cohort study (N = 3587), including 655 macrovascular events, 342 microvascular events (new or worsening nephropathy or retinopathy) and 632 all-cause mortality events during follow-up, in a secondary analysis of the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) study. For this study, phenylalanine, isoleucine, glutamine, leucine, alanine, tyrosine, histidine and valine were measured in stored plasma samples by proton NMR metabolomics. Hazard ratios were modelled per SD increase in each amino acid.

Results: In models investigating associations and potential mechanisms, after adjusting for age, sex and randomised treatment, phenylalanine was positively, and histidine inversely, associated with macrovascular disease risk. These associations were attenuated to the null on further adjustment for extended classical risk factors (including eGFR and urinary albumin/creatinine ratio). After adjustment for extended classical risk factors, higher tyrosine and alanine levels were associated with decreased risk of microvascular disease (HR 0.78; 95% CI 0.67, 0.91 and HR 0.86; 95% CI 0.76, 0.98, respectively). Higher leucine (HR 0.79; 95% CI 0.69, 0.90), histidine (HR 0.89; 95% CI 0.81, 0.99) and valine (HR 0.79; 95% CI 0.70, 0.88) levels were associated with lower risk of mortality. Investigating the predictive ability of amino acids, addition of all amino acids to a risk score modestly improved classification of participants for macrovascular (continuous net reclassification index [NRI] +35.5%, p < 0.001) and microvascular events (continuous NRI +14.4%, p = 0.012).

Conclusions/interpretation: We report distinct associations between circulating amino acids and risk of different major complications of diabetes. Low tyrosine appears to be a marker of microvascular risk in individuals with type 2 diabetes independently of fundamental markers of kidney function.

Trial registration: ClinicalTrials.gov NCT00145925.

Keywords: Amino acid; Diabetes complications; Metabolomics; Risk factors; Type 2 diabetes.

Conflict of interest statement

JC has received Research grants from Servier as Principal investigator for ADVANCE and for the ADVANCE-ON post trial follow-up study and honoraria from Servier for speaking about these studies at scientific meetings. MW reports receiving consulting fees from Amgen. PWu is an employee and shareholder of Nightingale Health Ltd, which conducted the biomarker quantification. All other authors declare that there is no duality of interest associated with their contribution to this paper.

Figures

Fig. 1

Flow diagram for design and sample analysis in the ADVANCE study of amino acids (note microvascular, macrovascular and all-cause mortality not mutually exclusive)

Fig. 2

Adjusted associations (model 2, log10 scale HR) of amino acids individually (per 1 SD increase) with macrovascular outcomes (a), microvascular outcomes (b) and all-cause mortality (c)