Background: The diagnostic process for chronic heart failure (CHF) in primary care settings often relies on the assessment of symptoms and clinical signs. However, the reliability of these indicators in identifying CHF within the broader community has not been extensively studied. This research aimed to determine the diagnostic value of symptoms, physical signs, and patient medical history in primary care for CHF.
Methods: This study included a diverse group of men and women in Portugal who visited 365 primary care centers for various health concerns, excluding acute infections, metabolic disorders, or pregnancy. Participants were selected for further cardiac evaluation if they achieved a score of three or more on categories one and two of the Boston questionnaire (covering medical history and physical examination findings) or were already receiving treatment for heart failure with loop or thiazide diuretics. Subsequent assessments included a resting echocardiogram to confirm cardiac dysfunction. The study then calculated sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratios (LR) to evaluate the diagnostic accuracy of different indicators.
Results: Out of 5434 participants, 1058 were referred for comprehensive assessment, and 551 were diagnosed with cardiac dysfunction at rest. Notably, a significant portion of these patients presented with less severe heart failure, with 35.5% classified as NYHA class I and 4.9% as class IV. The study identified several historical and clinical factors that significantly increased the likelihood of a heart failure diagnosis.
Historical Predictors: Prior use of digoxin (LR 24.9) and diuretics (LR 10.6) were strong indicators. A history of coronary artery disease (LR 7.1) also elevated the likelihood. Pulmonary oedema history showed a very high likelihood ratio (LR 54.2), suggesting a strong association with heart failure.
Symptomatic Predictors: Certain symptoms demonstrated significant diagnostic value. Paroxysmal nocturnal dyspnoea (LR 35.5), orthopnea (LR 39.1), and breathlessness during level walking (LR 25.8) were all strongly linked to a heart failure diagnosis. However, the study noted that these symptoms were not consistently present in all heart failure patients within this primary care population (sensitivity < 50%). This highlights that their absence does not rule out heart failure, especially in early stages.
Clinical Sign Predictors: Specific clinical signs were also found to be predictive. Jugular venous distension above 6 cm, measured from the sternal angle (LR 130.3), hepatic enlargement (LR 30.0), and lower limb oedema (LR 26.7) were highly indicative of heart failure. Additional signs included a ventricular gallop (LR 23.3), a heart rate exceeding 110 bpm (LR 26.7), and rales detected during pulmonary auscultation (LR 23.3). Similar to symptoms, these signs, while highly specific, had low sensitivity, meaning they were not consistently observed in all patients with heart failure.
Conclusions: This study underscores that while certain symptoms, clinical signs, and medical history elements can increase suspicion for heart failure in primary care, relying on them in isolation is insufficient for accurate diagnosis. The most predictive indicators are often associated with more advanced stages of heart failure. Limiting diagnostic investigations to patients exhibiting pronounced symptoms and signs would lead to missed diagnoses in a substantial proportion—potentially over 50%—of heart failure cases, particularly those with milder or atypical presentations. Therefore, a more comprehensive diagnostic approach, potentially including routine use of objective tests like echocardiography in at-risk primary care populations, may be necessary to improve early and accurate diagnosis of heart failure.
