Study Indicates Lymphocyte Count Predicts Death in Heart Failure

In this study, total lymphocyte count was a prognostic factor in patients with chronic heart failure and was inversely associated with predicted mortality.In contrast to earlier research, total lymphocyte count is an independent predictor of mortality in heart failure patients, a prospective study showed. After an an average 4.7 years of follow-up, the lymphocyte count was the second most prominent predictor of death, following New York Heart Association class, according to Gideon Charach, MD, of the Tel Aviv Sourasky Medical Center in Tel Aviv, and colleagues. And it was more significant than left ventricular ejection fraction, Charach and colleagues reported online in the American Journal of Cardiology. The prognostic value of the lymphocyte count has been previously explored, the researchers noted, but earlier studies were smaller and had follow-up times of less than a year. In contrast, Charach and colleagues enrolled 305 heart failure patients with up to 8.4 years of follow-up, prospectively evaluating lymphocytes, heart association class, left ventricular ejection fraction, and a host of laboratory parameters thought to be possibly related to mortality. The end point of the study was death from any cause or need for inpatient care. Over the course of the study, the researchers reported, 163 patients were hospitalized, all for exacerbation of heart failure, and 111 died. For analysis, the cohort was stratified according to median lymphocyte count (above or below 1,600 per milliliter), heart association class (I and II versus III or IV), and median ejection fraction (above or below 40%). The researchers found: On average, the total lymphocyte count was 1,803.64, and the left ventricular ejection fraction was 37%. Lymphocyte count below 1,600 was associated with a greater risk of death and hospital admission, at P=0.012 and P=0.024, respectively. Lymphocyte count greater than the median was associated with a 24% reduction in the risk of death (HR 0.76, 95% CI 0.37 to 0.97, P=0.037). Heart association class III or IV was associated with a doubling of the risk of death, compared with class I and II (HR 2.26, 95% CI 1.48 to 2.38, P<0.0001). Left ventricular ejection fraction of 40% or more was associated with a 40% reduction in the risk of death (HR 0.06, 95% CI 0.04 to 0.092, P=0.0138). Patients in heart association class I and II, but with a lymphocyte count below the median, had a poorer survival rate than those with more severe disease but a lymphocyte count of 1,600 or higher, a Cox regression analysis showed. There was no significant association between heart association class and left ventricular ejection fraction and the risk of morbidity, regardless of lymphocyte count, the researchers reported. The researchers said the study's strengths included the large number of patients and the long follow-up, but cautioned that the effect of hormone levels (adrenaline, cortisol, and parathyroid hormone) could not be evaluated because they were not measured. The authors did not report external support for the study or any conflicts.

Primary source: American Journal of Cardiology Source reference: Charach G, et al "Usefulness of total lymphocyte count as predictor of outcome in patients with chronic heart failure" Am J Cardiol 2011; DOI: 10.1016/j.amjcard.2010.12.049.