GOLD Criteria for COPD
The GOLD classifications are the main method doctors use to describe the severity of chronic obstructive pulmonary disease (COPD).
GOLD is short for the Global Initiative for Chronic Obstructive Lung Disease, a collaboration between the National Institutes of Health and the World Health Organization.
What Is GOLD Staging for COPD?
The GOLD staging system classifies people with COPD based on their degree of airflow limitation (obstruction). The airflow limitation is measured during pulmonary function tests (PFTs).
When blowing out forcefully, people with normal lungs can exhale most of the air in their lungs in one second. Pulmonary function tests measure this and other values, and are used to diagnose COPD and its severity:
- The volume in a one-second forced exhalation is called the forced expiratory volume in one second (FEV1), measured in liters.
- The total exhaled breath is called the forced vital capacity (FVC), also measured in liters.
- In people with normal lung function, FEV1 is at least 70% of FVC.
Because of lung damage, people with COPD take longer to blow air out. This impairment is called obstruction or airflow limitation. An FEV1 less than 70% of FVC can make the diagnosis of COPD in someone with compatible symptoms and history.
In GOLD COPD, classifications are then used to describe the severity of the obstruction or airflow limitation. The worse a person's airflow limitation is, the lower their FEV1. As COPD progresses, FEV1 tends to decline. GOLD COPD staging uses four categories of severity for COPD, based on the value of FEV1:
|Stage I||Mild COPD||FEV1/FVC<0.70||FEV1≥ 80% normal|
|Stage II||Moderate COPD||FEV1/FVC<0.70||FEV1 50-79% normal|
|Stage III||Severe COPD||FEV1/FVC<0.70||FEV1 30-49% normal|
|Stage IV||Very Severe COPD||FEV1/FVC<0.70||FEV1 <30% normal, or <50% normal with chronic respiratory failure present*|
* Usually, this means requiring long-term oxygen therapy.
What Do the GOLD COPD Classifications Mean?
The GOLD COPD criteria are an attempt by health experts to group people together based on the severity of their COPD. This process is called COPD staging. Accurate staging, or knowing the severity of your COPD, could have various benefits, such as:
- Helping people with COPD understand their disease better
- Helping doctors make better treatment recommendations for people with COPD
- Helping people with COPD plan for their future, and predict life expectancy
The GOLD COPD staging system can be helpful toward these goals. But the system is not accurate or precise enough to predict symptoms or life expectancy in individual people living with COPD.
One problem is that the GOLD COPD classifications only consider a person's degree of airflow obstruction. On average, people with severe airflow obstruction from COPD do have worse symptoms and a shorter life expectancy than people with mild obstruction. However, many other factors beside airflow obstruction influence breathing symptoms and life expectancy, such as:
- Overweight and obesity
- Smoking status
- Other medical conditions, especially heart disease
- Physical fitness and exercise habits