Baseline anemia was not an independent predictor of all-cause mortality in outpatients with heart failure (HF) and severe renal dysfunction or advanced heart disease in a study published Jan. 24 in the Journal of the American College of Cardiology.
Anemia is an independent prognostic marker in HF patients. Renal dysfunction, activation of neurohormonal and inflammatory responses, drug effects and bone marrow hyporesponsiveness all seem to contribute to the development of anemia in HF patients. However, the study authors suggested that estimates of the actual prevalence of anemia among HF patients vary widely due to differences in the definition of anemia and in investigated patient populations. Most previous studies have identified prevalence of anemia greater than 20 percent.
For this study, Bard Waldum, MD, from the Institute of Clinical Medicine at the University of Oslo in Norway, and colleagues evaluated the prognostic impact of anemia in outpatients with chronic HF attending specialized HF clinics. They specifically investigated its prognostic utility in patients with severe renal dysfunction or advanced HF.
They used multivariate Cox regression analyses to investigate the prognostic effect of anemia in 4,144 patients with HF from 21 outpatient HF clinics in Norway. Severe renal failure was defined as estimated glomerular filtration rate at least 45 ml/min/1.73 m2 and advanced HF as New York Heart Association (NYHA) functional classes IIIb and IV.
While baseline anemia was present in 24 percent and was a strong predictor of all-cause mortality, it did not predict mortality in the 752 patients with severe renal dysfunction and the 528 patients with advanced HF.
“[A]nemia—independent of cause—identified patients with a poor prognosis and should alert the clinician to the need for intensified care,” wrote Waldum and colleagues. “After adjustment for a large range of confounders, anemia remained a strong independent prognostic risk factor.”
In the 1,743 patients who attended subsequent visits, the researchers reported that sustained anemia independently predicted worse prognosis, whereas transient and new-onset anemia did not.
“The most striking finding in our study was that baseline anemia was not an independent predictor of all-cause mortality in the patients with severe renal dysfunction or the most advanced heart failure," the study authors wrote. “Impaired renal function and increasing NYHA functional class both independently predicted more serious prognosis in heart failure patients and were closely associated with anemia.”
They added, “Although baseline anemia did not affect mortality in the patients with advanced HF and severe renal dysfunction in our study, our data did not preclude that they suffer a high symptom burden from their anemia, and specific anemia treatment could be beneficial with regard to symptom relief.”