Apolipoprotein A-IV concentrations and clinical outcomes in haemodialysis patients with type 2 diabetes mellitus – a post hoc analysis of the 4D Study
Correspondence: Florian Kronenberg MD, Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Schöpfstr. 41, A-6020 Innsbruck, Austria.
(fax: +43 512 9003 73560 or 73561;e-mail: Florian.Kronenberg@i-med.ac.at).
Apolipoprotein A-IV (apoA-IV) is an anti-atherogenic and anti-oxidative plasma glycoprotein involved in reverse cholesterol transport. The aim of this study was to examine the association between apoA-IV and all-cause mortality, cardiovascular endpoints and parameters of protein–energy wasting and nutrition in haemodialysis patients.
This post hoc analysis was performed in the German Diabetes Dialysis Study (4D Study) evaluating atorvastatin in 1255 haemodialysis patients with type 2 diabetes mellitus, followed for a median of 4 years. The association between apoA-IV and relevant outcomes was analysed using Cox proportional hazards regression analyses. Body mass index (BMI) was used as a marker of protein–energy wasting. In addition, a definition of extended wasting was applied, combining median values of BMI, serum albumin, creatinine and sensitive C-reactive protein, to classify patients.
Mean (±SD) apoA-IV concentration was 49.8 ± 14.2 mg dL−1. Age- and gender-adjusted apoA-IV concentrations were strongly associated with the presence of congestive heart failure at baseline [odds ratio = 0.81, 95% confidence interval (CI) 0.74–0.88 per 10 mg dL−1 increase; P < 0.001). During the prospective follow-up, the strongest association was found for all-cause mortality [hazard ratio (HR) = 0.89, 95% CI 0.85–0.95, P = 0.001), which was mainly because of patients with BMI > 23 kg m−2 (HR = 0.87, 95% CI 0.82–0.94, P < 0.001) and those in the nonwasting group according to the extended definition (HR = 0.89, 95% CI 0.84–0.96, P = 0.001). This association remained significant after additionally adjusting for parameters associated with apoA-IV at baseline. Further associations were observed for sudden cardiac death. ApoA-IV was less strongly associated with atherogenic events such as myocardial infarction.
Low apoA-IV levels seem to be a risk predictor of all-cause mortality and sudden cardiac death. This association might be modified by nutritional status.