COPD Definition and Prevalence

Expert consensus defines COPD as a disease state characterized by airflow limitation that is not fully reversible, but is preventable and treatable. It generally involves two diseases, chronic bronchitis and emphysema. I want to emphasize the fact that this disease is preventable—because if we identify the risk factors, we can treat them—and that it is treatable. With appropriate pharmacotherapy, the patient is going to have an improvement in the airflow obstruction. The airflow limitation is usually progressive and is associated with an abnormal inflammatory response of the lungs to noxious particles. Although COPD affects the lungs, it also produces significant systemic consequences.

In my experience, I have found that over 90% of patients with COPD are treated by primary care physicians, family doctors, and internists. COPD could often be diagnosed earlier and treated sooner with more aggressive use of spirometry as a diagnostic tool in a patient who has risk factors for the disease, like being a smoker, or having been a smoker. The earlier the disease is diagnosed, the more successful treatment will be. Primary care physicians also need to address the issue of smoking cessation with patients and help them take advantage of the pharmacotherapy and support programs available.

COPD is not the same as asthma. They are both diseases of the lungs and associated with airway reactivity, but there are different precipitating factors. In COPD the airflow limitation is usually progressive and is associated with an abnormal inflammatory response in the lungs to a noxious stimulus, mainly smoke from smoking. In some parts of the world we have identified other risk factors like wood smoke and other pollutants. The airflow limitation is not fully reversible.

Asthma is a chronic inflammatory disorder of the airway that is associated with an increase in airway response. Patients with asthma will tell you "I was fine, I had no problems at all and suddenly I became very short-winded and it was very hard for me to breathe." Patients with COPD are always short-winded, always cough, are always limited. Patients with asthma have recurring episodes of wheezing, chest tightness, cough. Most of those occur mainly during the night or early in the morning. They are associated with changes in temperatures. They are very closely linked to environmental conditions like allergens in the air. Patients with COPD may experience some worsening of their symptoms because of these factors, but it is not going to be of the same intensity. They do not have a defined trigger that makes their condition worse. It is important to point out the significant differences between asthma and COPD and to understand that COPD is a more chronic disease in which much of the damage has been happening over a long period of time.

Although the effects of COPD are mainly in the lungs, we now recognize that it also produces significant systemic consequences. If we don’t provide appropriate therapy the disease progresses. Lung function and overall physical condition worsen and the patient deteriorates. There is also a high probability that a patient who has chronic lung disease also has coronary artery disease, arterial hypertension, and/or diabetes. There is an association of comorbid conditions that have to be taken into consideration and patients should be treated globally.

How prevalent is COPD? The disease can be characterized as an iceberg. The tip of the iceberg is a small number of patients who have severe lung disease. They have been identified, have been diagnosed and have likely had multiple hospitalizations. They are in treatment with either a primary care physician or a specialist. The next group is made up of a significant number of patients who have been diagnosed with moderate disease. Many of them are not receiving effective and appropriate pharmacotherapy.

The last group is the subclinical group, those below the surface. This is a huge number of people who have smoked in their lives and developed the disease but don’t know they have it. In order to identify these patients and institute therapy for them, we need to identify risk factors and use our tools to make a diagnosis.

Today, the prevalence of COPD is not only rising but is being diagnosed mainly in younger patients.
Over 70% of newly diagnosed patients with COPD are under the age of 65. Many of them are diagnosed due to emergency department visits, hospitalizations or outpatient visits. In the past we would start suspecting COPD in the 70 or 80-year-old male who had smoked in the past. Now we understand that we have to start looking for COPD in the younger patient.