ASN 2010: Risk of Atrial Fibrillation and Other CVD in CKD Patients

CKD stage is a predictor of incident AF and mortality risk in elderly patients. Patients with CKD also frequently exhibit major EKG abnormalities.

Selected posters focusing on mortality issues at Renal Week 2010, the 43rd Annual Meeting and Scientific Exposition of the American Society of Nephrology, shed additional light on the topics of atrial fibrillation (AF) and the cardiovascular variabilities of chronic kidney disease (CKD) patients.

The likelihood of incident atrial fibrillation, brought on by the disease and by dialysis treatment, was the central or adjunctive topic of study in numerous posters presented at the conference. Predictors of the complication was a particular focus of studies conducted by researchers at the University of Miyazaki Hospital in Miyazaki, Japan, and by Charles Herzog and Shuling Li, Minneapolis associates of the United States Renal Data System and Cardiovascular Special Studies Center.

The Japanese study, titled “Predictors and Mortality of Incident Atrial Fibrillation in Hemodialysis Patients,” observed the increased prevalence of AF in hemodialysis patients. Researchers identified the risk factors and predictive value of electrocardiographic assessment in incident AF, as well as the influence of AF on mortality in dialysis patients. A cohort of 299 patients (age, 63.1 ± 14.0 years; men, 59.2%; duration of HD, 80.3 ± 77.7 months) prescribed for dialysis therapy in two centers was retrospectively analyzed between December 2004 and December 2009.

In a multivariate analysis, lower hemoglobin levels, the presence of P-terminal force as a suggestive factor in enlarged left atriums, premature atrial contractions, and strain patterns were among the electrocardiographic findings reviewed to independently assess new onset of AF. Researchers noted that 37 patients had AF at enrollment, and of 262 patients who were in sinus rhythm at enrollment, 45 experienced newly developed AF during a follow-up period of five years.

The three-year survival rate of patients with incident AF and those who maintained sinus rhythm was 71.4% and 85.6%, respectively. The study concluded that left atrial enlargement, premature atrial contractions, and strain pattern were among the electrocardiographic findings that are predictive of new-onset AF in hemodialysis patients. Lower hemoglobin levels were also noted as predictive.

The Herzog-Li study examined CKD as a risk factor for AF in elderly patients. “Impact of Chronic Kidney Disease on Risk of Incident Atrial Fibrillation and Subsequent Survival in Medicare Patients” was based on an initial population of 1,092,649 patients age 66 and older in the General Medicare Database, with prior AF-incidence patients and end-stage renal disease patients excluded. The risk of developing AF was assessed in a model adjusted for demographics and comorbidity; a second model was employed to assess unadjusted survival following incident AF. A cohort of patients reviewed between 2006 and 2008 included 41% that were male and 88% that were white. Twenty-three percent of the patients were age 66-69; 25% were 70-74; 21% were 75-79; 16% were 80-84, and 14% were older than 85 years.

The review confirmed that CKD stage is a predictor of incident AF and subsequent mortality risk in elderly patients, and that AF frequency increases for CKD patients. Medicare patients with CKD and AF have a high (>30%) one-year mortality. The incidence of AF in patients filtered by stage was 7% in the population of patients not diagnosed with CKD; 11.1% with Stage 1 or 2 CKD; 12.4% with Stage 3, 4 or 5 CKD; and 11.6% in an undetermined stage

A third poster at Renal Week 2010 evaluated the importance of electrocardiogram (EKG) abnormalities as predictors of cardiovascular mortality in victims of CDK. “Electrocardiogram Abnormalities and Cardiovascular Mortality in Patients with Chronic Kidney Disease” was the focus of researchers at two hospitals and at Case Western Reserve University in Cleveland.

Research drew on entries to the Cardiovascular Health Study limited database between 1989 and 2005 to identify a cohort of patients with CKD at a baseline eGFR<60 mL/min/1.73m2. The study population was categorized as having major, minor or no EKG abnormalities. Rates of cardiovascular events and mortality were compared between three groups using proportional hazards regression analysis.

A total of 1,192 patients had CKD at baseline. Of these, 38.8% reflected major EKG changes, 29.7% had minor EKG changes and 31.5% had no EKG changes. Cardiovascular-based cause of death was identified in 54.4% of the patients with major EKG changes, 28.1% of those with minor EKG changes and 17.5% of patients with no EKG changes. The study concluded that patients who have CKD defined as eGFR<60 mL/min/1.73m2 frequently exhibit major EKG abnormalities. These abnormalities predict significantly higher risks of negative cardiovascular outcomes and mortality.