A prognostic index to predict long‐term mortality in patients with mild to moderate chronic heart failure stabilised on angiotensin converting enzyme inhibitors

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Abstract
Background: Mortality in patients with mild to moderate chronic heart failure remains high. At present there is no easy way of identifying patients within this population at increased risk of death in the medium to long term.Aims: To develop a prognostic index to identify outpatients with mild to moderate chronic heart failure at increased risk of death.Methods and results: Five hundred and fifty‐three outpatients mean (S.D.) age 63(±10) years with symptoms of chronic heart failure (mean New York Heart Association functional class, 2.3(±0.5)), were recruited between December 1993 and April 1995. By April 2000, 201 patients had died. Using data from non‐invasive measurements of cardiac size, electrical and autonomic function, renal function and plasma biochemistry we identified eight independent predictors of mortality (allP<0.01). To develop a prognostic index, predictors were dichotomised by group median and awarded 0 or 1 point accordingly. Serum sodium≤140 mmol/l (1 point), creatinine≥111 μmol/l (1 point), cardiothoracic ratio≥0.52 (1 point), SDNN≤112 ms (1 point), maximum corrected QT interval≥487 ms (1 point), QRS dispersion≥42.7 ms (1 point), the presence of non‐sustained ventricular tachycardia (1 point) and voltage criteria for left ventricular hypertrophy on 12‐lead ECG (1 point). We calculated risk scores for patients by adding the points of each independent risk factor. In the low‐risk group (0–3 points) mortality at 5 years was 20% and in the high‐risk group (4–8 points) 53%. The area under the receiver–operator characteristic curve using dichotomised variables was 0.74 and for continuous model 0.78.Conclusions: Our prognostic index which uses eight non‐invasive measurements and a straightforward additive points system, has good discrimination and stratifies outpatients with chronic heart failure into high and low risk. This index may be useful in clinical care and risk stratification.