Background: Accurate diagnosis is the cornerstone of effective treatment for chronic obstructive pulmonary disease (COPD) and asthma. However, in primary care settings, patients receiving inhaled therapy may not always receive diagnoses that align with current best practice guidelines. This study investigates the diagnostic landscape in primary care, focusing on the challenges of differential diagnosis for respiratory conditions.
Aim: This research aims to analyze the characteristics of patients in primary care who are treated with inhaled medications. A key objective is to assess the consistency of different diagnostic tools used for differential diagnosis of COPD and asthma. Furthermore, the study evaluates the appropriateness of inhaled corticosteroid (IC) prescriptions within this patient population in primary care.
Design and Setting: This cross-sectional, multicenter, non-interventional study was conducted across 10 primary care centers located in Barcelona, Spain. The primary care setting is crucial for understanding real-world diagnostic practices and treatment patterns for respiratory diseases.
Method: The study included patients over 40 years of age with chronic respiratory disease who were undergoing treatment with inhaled corticosteroids (ICs). Data collection involved gathering sociodemographic and clinical information from these patients. A vital component of the study was the performance of forced spirometry, including a bronchodilator test (BDT), to objectively assess lung function. To further evaluate diagnostic accuracy, two distinct differential diagnosis questionnaires were administered, providing a comparative perspective on diagnostic approaches beyond standard clinical assessment.
Results: Initially, general practitioners (GPs) classified 328 patients into diagnostic categories: COPD (64.8%), asthma (15.4%), or indeterminate respiratory condition (19.8%). Following spirometry testing, a significant proportion (40%) of patients exhibited moderate-to-severe airflow obstruction according to the GOLD classification, a widely recognized standard for COPD severity. The mean reversibility of forced expiratory volume in 1 second (FEV1) was 8.4%, and 18.6% of patients showed a positive bronchodilator test (BDT), indicating potential reversibility of airflow limitation, often seen in asthma. Notably, 39.8% of patients had a post-bronchodilator FEV1/forced vital capacity ratio greater than 0.7, a finding that can complicate the differential diagnosis between COPD and asthma.
The study revealed varying degrees of agreement between different diagnostic methods. Moderate concordance was observed between clinical diagnoses made by GPs and spirometry results, as well as between the two differential diagnosis questionnaires. However, concordance was low between clinical diagnoses and the questionnaire results, suggesting discrepancies in diagnostic approaches. Alarmingly, very low concordance was found between spirometry results and the differential diagnosis questionnaires, highlighting significant inconsistencies across diagnostic tools. Regarding treatment, a substantial 71.4% of patients diagnosed with COPD were being treated with inhaled corticosteroids (ICs), despite guidelines recommending caution in IC use for COPD in the absence of specific indications. Conversely, 12% of patients classified as having asthma were not receiving inhaled corticosteroids, potentially indicating undertreatment in this group.
Conclusion: Primary care physicians are generally able to classify most patients with chronic respiratory symptoms as having either COPD or asthma. However, the study findings indicate that relying solely on clinical symptoms and spirometry with a bronchodilator test may not be sufficient for optimal Primary Care Differential Diagnosis. The use of the two differential diagnosis questionnaires in this study did not demonstrate a significant improvement in differential diagnostic accuracy compared to traditional methods. The observed misdiagnosis and discrepancies between diagnostic approaches may contribute to inadequate treatment strategies for both COPD and asthma in primary care. These findings underscore the need for improved strategies and tools to enhance primary care differential diagnosis in respiratory medicine, ultimately leading to more targeted and effective patient care.
