Heart rate variability may predict risk for kidney disease
MedWire News: Low heart rate variability (HRV), a measure of poor autonomic function, may increase the risk for developing chronic kidney disease (CKD), a US study suggests.
Daniel Brotman (Johns Hopkins University School of Medicine, Baltimore, Maryland) and colleagues explain: "The glomerulus is adversely affected by the same pathophysiological factors that lead to atherosclerosis.
"Given that these risk factors for cardiovascular disease are also associated with high sympathetic and low parasympathetic tone, it is not surprising that HRV and other measures of autonomic tone are related to the progression of renal dysfunction."
The researchers assessed the resting heart rate and HRV of 13,241 participants aged 45 to 64 years, every 3 years, from 1987 to 2004 (median 16 years).
The team assessed heart rate parameters in quartiles. As "lower resting heart and greater beat-to-beat variability in heart rate (high HRV) are associated with a healthy autonomic nervous system and good cardiovascular health," they defined at-risk groups as those patients in the lowest HRV quartile (n=3152) and the highest resting heart rate quartile (n=3310).
Cases of end stage renal disease (ESRD) and CKD-related hospitalizations were also monitored.
The results, published in the Journal of the American Society of Nephrology, showed that 199 cases of ESRD and 541 CKD related hospitalizations occurred during the follow-up period.
The team found a higher rate of ESRD among the at-risk group of patients for HRV compared with all other patients, at 3.1% versus 1.0%, respectively (p<0.001). After adjustment for variables such as age and race, at-risk HRV and at-risk resting heart rate groups had a 98% and 56% increased ESRD risk, respectively.
CKD related hospitalization rates showed the same pattern, at 6.7% versus 3.2% for the at-risk group of patients for HRV compared with all other patients, respectively (p<0.001).
Patients in the at-risk group for both HRV and resting heart rate (n=745) were found to have a 3.4-fold increase risk compared with all other patients.
Although the researchers note that the findings do "not demonstrate a cause-and-effect relationship," they say that "the temporal pattern is intriguing in that abnormal HRV preceded the development of clinical renal failure by many years."
They conclude: "Rather than suggesting a change in clinical practice, we hope our findings will encourage further research to better define the putative role of the autonomic nervous system in precipitating and exacerbating renal disease in human."
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By Lauretta Ihonor