Many people who suffer from chronic kidney disease progressively lose their kidney function over time and eventually develop a condition called end-stage renal disease - the complete failure of the kidneys - placing them in need of lifelong dialysis or a kidney transplant.
Now researchers at the University of California, San Francisco (UCSF) and the Kaiser Permanente Northern California Division of Research have found that the risk of kidney failure is greater for people with chronic kidney disease who also have atrial fibrillation, one of the most common forms of irregular heart rhythm in adults.
The finding opens the way for further studies into the relationship between the two factors, which could lead to new treatment approaches that would improve outcomes for people with chronic kidney disease.
Doctors have known that patients with chronic kidney disease or end-stage renal disease commonly have atrial fibrillation and as a result are more likely to have a stroke or to die. However, the long-term impact of atrial fibrillation on kidney function among patients with known chronic kidney disease has been unknown.
The new study, published last month in the journal Circulation, involved 206,229 adults with chronic kidney disease who were drawn from members of Kaiser Permanente Northern California, a large integrated health care delivery system.. Over the course of about five years, approximately 16,400 patients developed atrial fibrillation, and those who did were 67 percent more likely to progress to end-stage renal disease compared with patients who had chronic kidney disease but did not develop atrial fibrillation
"These novel findings expand on previous knowledge by highlighting that atrial fibrillation is linked to a worse kidney prognosis in patients with underlying kidney dysfunction," said kidney specialist Nisha Bansal, MD, an assistant professor in the Division of Nephrology at UCSF.
"There is a knowledge gap about the long-term impact of atrial fibrillation on the risk of adverse kidney-related outcomes in patients with chronic kidney disease," said senior author Alan S. Go, MD, director of the Comprehensive Clinical Research Unit at the Kaiser Permanente Division of Research. "This study addresses that gap and may have important implications for clinical management by providing better prognostic information and leading to future work determining how to improve outcomes in this high-risk group of patients."
UCSF is one of the world's leading centers for kidney disease treatment, research and education. Its Division of Nephrology is ranked among the best programs in the nation by U.S. News & World Report.
Beating the Odds
People who have chronic kidney disease fall into a spectrum in terms of how severe their disease is. At one end are those who have very minor loss of kidney function. They may not have any symptoms at all, and only by applying a simple blood test can doctors properly diagnose their disease.
At the other end of the spectrum are the people who have progressed to end-stage renal disease, which is basically complete kidney failure. They require lifelong dialysis or a kidney transplant. Some people progress rapidly to end-stage renal disease while others may live for decades without ever progressing.
Doctors are interested in understanding the factors that place patients at greater risk for end-stage renal disease, Bansal said, because it may be possible to address those factors through medications or lifestyle changes like diet or exercise.
Bansal added, however, that while the two conditions are intertwined, scientists do not know exactly which specific genes, pathways and biological mechanisms connect irregular heartbeat to declines in kidney function. Neither do they yet know the extent to which treating atrial fibrillation will improve outcomes for people with chronic kidney disease.
The article, "Incident Atrial Fibrillation and Risk of End-Stage Renal Disease in Adults with Chronic Kidney Disease" is authored by Nisha Bansal, Dongjie Fan, Chi-yuan Hsu, Juan D. Ordonez, Gregory M. Marcus and Alan S. Go. It was published online by the journal Circulation on Dec. 28, 2012. See: http://dx.
This work was funded by the National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK) and the National Heart, Lung and Blood Institute (NHLBI) through grant #K23 DK088865, #K24 DK92291, #5U01 DK060902, #5U19 HL091179 and #5 RC2 HL101589. Both NIDDK and NHLBI are components of the National Institutes of Health.
UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care.
The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and the society at large. It seeks to understand the determinants of illness and well-being and to improve the quality and cost-effectiveness of health care. Currently, DOR's 600-plus staff is working on more than 250 epidemiological and health services research projects. For more information, visit www.dor.kaiser.org.