Stage of Kidney Disease Affects Heart Failure Risk


SAN DIEGO — The more advanced the stage of chronic kidney disease, the greater the risk of developing heart failure and subsequent risk of death, results from a large analysis of Medicare patients showed.

“Even a modest degree of chronic kidney disease is a very strong predictor of having cardiovascular morbidity and mortality,” Dr. Charles A. Herzog said in an interview at the annual meeting of the American Society of Nephrology.

“Chronic kidney disease is something that primary care physicians can easily detect, because it's very easy to do a serum creatinine in an office setting,” said Dr. Herzog, director of the Minneapolis–based cardiovascular special studies center of the U.S. Renal Data System Coordinating Center.

He identified just over 1 million patients aged at least 66 years from the general Medicare database and followed them during 2006-2007. Patients with heart failure and end-stage renal disease at baseline were excluded from the analysis.

The researchers used a Cox proportional hazard model to assess the patients' risk of developing incident heart failure, adjusting for demographics, comorbidities, and stage of chronic kidney disease. They used the Kaplan-Meier method to estimate the age-adjusted survival of patients after the development of incident heart failure.

At baseline, 59% of the patients were women and 88% were white. Most (95.8%) had no chronic kidney disease, 0.4% had stage I-II disease, 1.4% had stage III-IV disease, and the remainder (2.4%) had an unknown stage of disease.

After 1 year, heart failure occurred in 5.3% of patients with no chronic kidney disease at baseline, 12.7% of those with stage I-II disease, 15% of those with stage III-IV disease, and 12.3% of those whose disease stage was unknown.

Independent predictors of heart failure were age 70-74 years (hazard ratio 1.30); age 75-79 years (HR 1.75); age 80-84 years (HR 2.42); and age 85 years and older (HR 3.82). Other independent predictors included black race (HR 1.21); stage I-II chronic kidney disease (HR 1.45); stage III-IV disease (HR 1.68), and unknown stage of chronic kidney disease (HR 1.27).

Dr. Herzog also found that the the following comorbid conditions predicted heart failure: anemia (HR 1.22), diabetes (HR 1.57), ischemic heart disease (HR 1.67), and dysrhythmia (HR 1.94).

Over the 1-year period, 83% of patients with no chronic kidney disease survived, compared with 77% of those with stage I-II disease, 75% of those with stage II-IV disease, and 67% of those whose disease stage was unknown.

Dr. Herzog acknowledged that a limitation of the study was its reliance on Medicare claims data.

Dr. Herzog is a consultant for Amgen Inc., a scientific adviser for CorMedix Inc., and a trustee of the Roche Foundation for Anemia Research.

'A modest degree of chronic kidney disease is a very strong predictor' of cardiovascular morbidity and mortality,


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