Impact of the apolipoprotein B/apolipoprotein A-I ratio on renal outcome in immunoglobulin A nephropathy

Abstract

Objective.Serum levels of the apolipoprotein B/apolipoprotein A-I ratio (ApoB/ApoA-I) have been shown to identify patients at risk of cardiovascular disease. The aim of this study was to evaluate whether raised ApoB/ApoA-I values are also predictive of renal outcome in patients with chronic kidney disease (CKD), as similar mechanisms seem to be involved in the development of atherosclerosis and glomerulosclerosis. Only patients with immunoglobulin A nephropathy (IgAN) were included, since they represent a homogeneous group of patients with CKD. Material and methods. ApoB and ApoA-I, serum albumin, urine albumin and blood pressure were measured, and a highly sensitive C-reactive protein test was carried out, in 70 patients with IgAN and in 70 age- and gender-matched healthy control subjects. Patients were followed over a period of up to 11 years (median 3.8 years). End-stage renal disease (ESRD) was defined as reaching CKD stage 5 [estimated glomerular filtration rate (eGFR) <15 ml/min/1.73 m²]. Results.Baseline ApoB/ApoA-I values greater than 0.9 for men and greater than 0.8 for women were associated with a risk of developing CKD stage 5 (risk ratio 5.7, p = 0.037), independently of baseline GFR and serum albumin. Conclusion. Patients with IgAN and an increased ApoB/ApoA-I ratio have a significantly higher risk of developing ESRD compared with patients with a low ratio. Controlled studies are warranted to demonstrate whether interventions focusing on the ApoB/ApoA-I ratio may have beneficial clinical effects.

Key Words::

• apolipoproteins
• chronic renal disease
• IgA nephropathy
• prognostic factor

Acknowledgements

We thank Rose-Marie Åkers, Anette Bygden-Nylander and Åsa Lindé (Department of Nephrology, Karolinska University Hospital) and Eva Jemseby (Department of Rheumatology, Karolinska University Hospital) for excellent assistance, and Elisabeth Berg (MedStat LIME, Karolinska Institute) for help with statistical analysis. This study was supported by grants from the Karolinska Institutet and the Fund for Renal Research, Sweden.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.