Haptoglobin Phenotype Predicts a Low Heart Rate Variability in Patients with Chronic Kidney Disease

F-PO1096

Haptoglobin Phenotype Predicts a Low Heart Rate Variability in Patients

with Chronic Kidney Disease My Svensson,1 Charlotte Strandhave,1 Henrik

My Svensson,1 Charlotte Strandhave,1 HenrikKrarup,2 Jeppe H. Christensen.1 1Department of Nephrology, Aalborg Hospital,

Aalborg, Denmark; 2Department of Clinical Biochemistry, Aalborg Hospital,

Aalborg, Denmark.

Introduction

Three major phenotypes for the haptoglobin (Hp) gene has been identified: Hp 1-1, Hp

2-2, and the heterozygous Hp 2-1. Hp 2-2 is associated with a poor outcome in patients with

cardiovascular disease. This may be due to a phenotype-dependent antioxidant capacity

where Hp 2-2 exhibits a low antioxidant ability, increasing the risk of cardiovascular disease.

An attenuated heart rate variability (HRV) may be an important predictor of mortality in

patients with chronic kidney disease (CKD). In the present study, we examined whether Hp

phenotyping in patients with CKD could identify a group of high-risk patients according

to HRV measurements.

Methods:

Patients (n = 61) were recruited from our outpatient clinic. They were eligible if

they had CKD, defined as a plasma creatinine level between 1.70 and 4.52 mg/dL, for

more than 3 months. The Hp phenotype was determined using a high-performance liquid

chromatography. Furthermore, a 24-hour Holter recording was obtained in each patient

for analysis of 24-h HRV indices in the time domain.

Results:

The CKD patients in the three groups [phenotypes Hp 1-1 (n=12), Hp 2-1 (n=32),

and Hp 2-2 (n=17)] were comparable regarding clinical relevant parameters such as age,

plasma creatinine, body mass index, PTH level, and haemoglobin. Furthermore, sodium-,

potassium-, and calcium levels were within normal range in all patients. The HRV parameter

SDNN (SD of all normal RR-intervals) was 129 ms (+ 43) in Hp 1-1, 126 ms (+ 36) in Hp

2-1, and 102 ms (+ 31) in Hp 2-2 (p = 0.02). Furthermore, SDANN (SD of the mean of all

normal RR intervals measured in successive 5-min periods) was 111 ms (+ 45) in Hp 1-1,

114 ms (+ 35) in Hp 2-1, and 92 ms (+ 30) in Hp 2-2 (p = 0.04). Several other HRV indices

showed a similar trend with the lowest HRV in patients with phenotype Hp 2-2.

Conclusion

Haptoglobin phenotyping in patients with CKD revealed that patients with Hp 2-2 had

a significantly lower HRV compared to the other two phenotypes. Thus, Hp 2-2 phenotype

may identify a group of high-risk CKD patients.

Disclosure of Financial Relationships: nothing to disclose