Diagnosis, Assessment, and Classification
COPD is diagnosed through a combination of spirometry and medical history, including symptom history and presence of risk factors. Spirometry is a noninvasive, readily available, objective measure of airflow limitation. Spirometry is required to make an official diagnosis of COPD with a postbronchodilator forced expiratory volume/forced vital capacity (FEV1/FVC) <0.70 confirming persistent airflow limitation. Key risk factors include smoking status and occupational or environmental exposures. Common symptoms of COPD include dyspnea, cough, sputum production, wheezing, and chest tightness. When assessing symptoms, it is important to consider differential diagnosis, especially during the COVID-19 pandemic, as noted by the updated Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines.
The 2021 GOLD guidelines recommend that the use of spirometry be limited to only patients who require urgent or essential testing for diagnosis and/or to assess lung function for interventional procedures or surgery, as such testing may lead to viral transmission. A safer alternative may be the use of home measurement of peak expiratory volume and the use of validated patient questionnaires. These questionnaires are completed via an interview to determine respiratory health, symptoms, comorbidities, and risk factors for developing COPD.
Symptoms of COPD and COVID-19 infection may overlap. The two main overlapping symptoms are cough and shortness of breath. Some of the symptoms that favor COVID-19 include fever, hypoxia, loss of smell or taste, headaches, and lymphopenia. The SARS-CoV-2 virus may also cause pathophysiologic changes such as vascular injury, pneumonitis associated with hypoxemia, coagulopathy, high levels of systemic inflammation, and multiorgan involvement.
The GOLD guidelines classify patients into four different categories: GOLD 1 (mild), GOLD 2 (moderate), GOLD 3 (severe), or GOLD 4 (very severe) based on their level of airflow limitation. This is assessed by evaluating a postbronchodilator FEV1/FVC. Refer to Table 1 for more information regarding FEV1 values and GOLD classification.
The Modified British Medical Research Council (mMRC) Questionnaire and COPD Assessment Test (CAT) are the two most widely used measures to assess symptoms of COPD. The mMRC is used to assess breathlessness of patients with COPD. It consists of grades 0 to 4, with grade 0 indicating breathlessness only with strenuous exercise and grade 4 indicating breathlessness that affects activities of daily living as well as the ability to leave the house. The CAT is an eight-item measure of impairment experienced from COPD, with scores ranging from 0 to 40. Higher scores on the CAT indicate a larger impact of COPD on the patient's life.
Symptom burden and risk of exacerbation are also further classified into GOLD groups A through D, which is used to guide therapy. Classification is patient-specific, and each patient's treatment regimen should be tailored specifically to their needs. Refer to Figure 1 for the GOLD group classification algorithm.
The Refined ABCD Assessment Tool
ABCD: Group A low risk/low symptoms, Group B low risk/high symptoms, Group C high risk/low symptoms, Group D high risk/high symptoms; CAT: COPD Assessment Test; FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; GOLD: Global Initiative for Chronic Obstructive Lung Disease; mMRC: modified British Medical Research Council.
Source: Reference 1. Reprinted with permission.
US Pharmacist. 2021;46(7):30-36. © 2021 Jobson Publishing