[Mortality prognosis factors in heart failure in a cohort of North-West Spain. EPICOUR study]

Abstract

Aims: Heart failure (HF) is a serious health problem in Spain because it has a high mortality rate and causes considerable costs to the health-care system. This paper presents a study made in the Spanish province of Ourense to study the survival of patients with HF related to the ventricular function or other possible risk factors (RF) associated with the HF prognosis.

Material and methods: A prospective cohort study was performed, considering any patient hospitalized due to HF from 1 January 1999 to 31 December 2002 (5318 patients) who had undergone an echocardiography that showed systolic or diastolic dysfunction as potential participants (2387 patients). After at least 24 months of the index episode of hospitalization, a sample of 2384 patients was chosen by random sampling. The principal measurement was based on survival and the differences observed in the performance of the left ventricular ejection fraction, of functional class (FC) of HF and of other clinical and epidemiological characteristics. The Kaplan-Meier, log-rank and Cox tests were used.

Results: Mean age of the patients 74.84 (range 36-95); 53.4% males and 56.5% first admission. The most common antecedent was arterial hypertension (HTA) (59.9%), followed by valvulopathy (41.9%) and heart disease (HD) (26.8%). A total of 44.3% of the patients had atrial fibrillation-flutter (AF). Global survival at 5 years was 47.9% and specific survival rate for HF was 74.8%. There were no significant differences in survival between patients with heart failure and preserved systolic function (HF-PSF) and those who suffered systolic dysfunction (p=0.248). Prognostic factors of mortality in patients with HF are: advanced functional class (class III-IV) prior to admission (Hazard ratio [HR] 5.37), deterioration of the glomerular filtration rate (GFR) (HR 0.98), hypoalbuminemia (HR 0.59), hyponatremia (HR 0.93) and hyperkalemia (HR 1.79). The Castelli index higher than 4.5 is in the limit of statistical significance.

Conclusions: Global survival rate observed at 5 years of research is similar to the results found in already-published papers. Specific survival rate for HF is lower and there are no differences in the survival rate with regard to the left ventricle ejection fraction (E(f)). However, we show that hypoalbuminemia, hyperkalemia and high Castelli index are important prognostic factors of mortality in patients with HF.