Aim: To estimate the prevalence of chronic heart failure (CHF) in mainland Portugal in 1998. Methods and population: A community-based epidemiological survey involving subjects attending primary care centres selected by a combined two-stage sampling and stratified procedure. General practitioners (GPs) randomly selected in proportion to the population of the District, evaluated subjects attending primary care centres aged over 25 years, recruited consecutively and stratified by age. CHF cases were identified according to the Guidelines of the European Society of Cardiology for CHF diagnosis. Results: 5434 eligible subjects were evaluated by 365 GPs; 551 patients with CHF were identified. The overall prevalence and 95% CI of CHF in mainland Portugal is 4.36% (3.69-5.02%), 4.33% in males (3.19-5.46%), and 4.38% in females (3.64-5.13%). Age-specific CHF prevalence was as follows: 1.36% in the 25-49 years-old group (0.39-2.33%), 2.93% in the 50-59 years-old group (5.58-9.37%), 7.63% in the 60-69 years-old group (5.58-9.37%), 12.67% in the 70-79 years-old group (10.73-14.6%), and 16.14% in group over 80 years old (13.81-18.47%). The prevalence of CHF due to systolic dysfunction was 1.3% and the prevalence of CHF with normal systolic function was 1.7%. Conclusions: The overall prevalence of CHF in Portugal was slightly higher than that of other European studies and increases sharply with age. The prevalence of CHF due to systolic dysfunction is very similar to that reported by other recent European studies. The differences found may correspond to differences in methodology rather than actual differences in the population.

Background: The value of symptoms and signs in the diagnosis of CHF has rarely been tested in large numbers of patients in the community. The aim of this study was to evaluate the importance of symptoms, signs, and past medical history in the diagnosis of CHF in primary care. Methods: Data on a sample of Portuguese men and women attending 365 primary care centres for any condition other than the treatment of acute infection, metabolic conditions or pregnancy were collected. All subjects who scored three or more points in the sum of categories one and two of the Boston questionnaire (history and physical examination) and those being treated for heart failure with loop or thiazide diuretics were considered to have possible heart failure and referred for further assessment including a resting echocardiogram. The sensitivity, specificity, positive predictive value, negative predictive value and likelihood ratio (LR) for the diagnosis of heart failure were calculated. Results: A total of 5434 subjects were identified, of whom 1058 fulfilled the criteria for further assessment; 551 subjects had cardiac dysfunction at rest, of which 35.5% were in NYHA class I and 4.9% in class IV. Prior use of digoxin (LR 24.9) and/or diuretics (LR 10.6), a history of coronary artery disease (LR 7.1) or of pulmonary oedema (LR 54.2), were associated with a greater likelihood of having heart failure. Amongst current symptoms, a history of paroxysmal nocturnal dyspnoea (LR 35.5), orthopnea (LR 39.1) and breathlessness when walking on the flat (LR 25.8) were associated with a diagnosis of heart failure. However, these symptoms were not frequent amongst patients with heart failure within this population (sensitivity b36%). Jugular pressure N6 cm with hepatic enlargement, and oedema of the lower limbs (LR 130.3), a ventricular gallop (LR 30.0), a heart rate above 110 bpm (LR 26.7), and rales at pulmonary auscultation (LR 23.3) were all associated with a diagnosis of heart failure, but were infrequent findings in patients with heart failure (sensitivity b10%). Conclusions: Symptoms and signs, and clinical history had limited value in diagnosing heart failure when used alone. The signs and symptoms that best predicted a diagnosis of heart failure were those associated with more severe disease. If investigation is limited to patients with more definite symptoms and signs of heart failure, fewer than 50% of cases will be identified and a large number of patients with mild symptoms will be missed.

Aim: To validate and estimate the performance statistics and concordance of seven clinical questionnaires for the diagnosis of chronic heart failure (HF). Methods: Community-based epidemiological survey of patients aged N25 years attending a random sample of primary health care centers in Portugal. Heart failure was identified according to the Guidelines of the European Society of Cardiology (ESC). Results: A total of 5434 subjects evaluated by 365 investigators were eligible for analysis, 551 of which had criteria for heart failure. Overall, the questionnaires had high specificity, usually above 90%, but low sensitivity, providing an increase in the likelihood of heart failure from 4.3% pre-test to 25-35% post-test in most cases. The Gfteborg questionnaire was the most balanced regarding sensitivity (84%) and specificity (81%) but this may reflect its use of prescription of digoxin or diuretics as diagnostic criteria for diagnosis. The Walma, Framingham and NHANES-I questionnaires performed similarly (Sensitivity: 63%, Specificity: 93%), while the Boston and the Gheorghiade questionnaires had a somewhat lower sensitivity (55%). Concordance was good between the Boston, Framingham, Gheorghiade, NHANES-I and Walma questionnaires. Conclusions: This study evaluated seven clinical questionnaires for the diagnosis of heart failure in the community. Their low sensitivity impairs their usefulness as diagnostic instruments, but their high specificity makes them useful for the identification of patients with fluid retention and/or exercise intolerance from non-cardiac causes.