Stages of COPD

Some of the most common questions asked by people with COPD are: "What are the stages of COPD?" "What stage am I in now?" and "What can I expect in the future?"

Well, the answer is not as clear-cut as it used to be because we’re learning more and more that COPD is not a "one-size-fits-all" disease.

The severity stages of COPD have been based on the results of a spirometry / lung function test which assesses how your lungs function compares to values of healthy people your age, race and height. While it’s important to have a spirometry test and know your % predicted values of FEV1 and your FEV1/FVC ratio (these terms are explained below), that doesn’t tell us everything about how your health and symptoms will progress over the next few years.

Different “types” of COPD

We know now that there are different "types" of COPD. Each type may affect how well different treatments work and how your symptoms like shortness of breath may progress. In addition, if you have another condition (called "comorbidities") , such as heart disease, diabetes, depression, or anxiety that can also affect your COPD, its treatment and what your COPD may be like at each "stage".

What are FEV1 and FVC?

Spirometry is a simple, non-invasive test that is used to diagnose COPD. When you take the test, you will be asked to blow all the air out of your lungs into a mouthpiece connected to a machine known as a spirometer. The technician tells you to take in a really deep breath, blast it out fast, then keep blowing and blowing as long as possible.

The machine will calculate two numbers, the amount of air you blow out in the first second, and the amount of air you can completely blow out and compare it to the values of a person your age, your height, and your race, with normal, healthy lungs.

These numbers are represented as FEV1 and FVC. FEV1 stands for the forced expiratory volume in the first second — the amount of air you forcefully exhaled in the first second of blowing. FVC stands for forced vital capacity— the amount of air that you completely exhale in one breath.

 

What Spirometry Measures

 

Lung function doesn’t tell us everything

Let’s say there are three people, John, Sue, and Dave. They all have a FEV1 of 35% of predicted for their age and sex. You might think they all have similar symptoms or are impacted by COPD in the same way. But, in reality, their ability to do physical activities, their tendency to have COPD flare-ups (exacerbations) and even their level of blood oxygen (oxygen saturation number on a pulse oximeter) may be very different. John might be able to walk farther than Sue, but every time he gets a cold, it becomes a COPD exacerbation that really knocks him down. Sue hasn’t been really sick with breathing problems (had an exacerbation) for a few years. John and Sue’s oxygen saturation numbers are good, but Dave’s numbers get low when he walks, so he uses supplemental oxygen. With his oxygen, Dave can walk farther than John and Sue. How can that be?

It’s because spirometry numbers are just one aspect of determining what’s going on with your COPD and what kind of impact it has on your everyday life.

What other things tell us about your COPD?

Here are some things that may help determine if you have one of the known types of COPD. Knowing these can be useful information in addition to knowing your spirometry numbers.

  • If you have shortness of breath, is it at rest or only with exertion?
    • Shortness of breath usually gets worse as the stage of COPD gets worse but for many people this can be improved with regular activity or by attending pulmonary rehabilitation.
  • Do you have a cough? If so, do you cough up sputum on most days for at least three months in a period of at least two years?
    • This suggests that you may have the chronic bronchitis type of COPD which may respond to different medicines.
  • Do you have a lower oxygen level at rest, only with exertion, or when you sleep?
    • No matter what your lung function is, treating your other conditions and getting them under control can improve what is happening with your COPD.
  • Are your lungs stretched out and bigger than normal? If so, are they stretched out throughout your whole lung or just in certain places?
    • This is emphysema which is diagnosed by a radiology test (a chest X-ray or a computed tomography [CT] scan) which can affect how your COPD progresses and what treatments may help. Sometimes it is possible to decrease the size of the big, stretched out places in your lungs.
  • Do you have any chronic conditions in addition to COPD (known as “comorbidities”), such as heart disease, diabetes, anxiety, or depression?
    • No matter what your lung function is, treating your other conditions and getting them under control can improve what is happening with your COPD.

All these factors can have a significant impact on your everyday life. All should be taken into account to find the best way to manage your particular type of COPD. Remember, we do use the FEV1 and other lung function numbers to guide recommendations for care of your COPD.

Understanding spirometry results is important

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2020 strategy recognizes the importance of other features of COPD such as symptoms assessed by questionnaires (COPD Assessment Test [CAT], modified Medical Research Council test [mMRC]) or exacerbations but lung function remains an important tool to define the severity of your airflow limitation and helps guide your treatment with inhaled medications (bronchodilators).

GOLD stages in individuals with an FEV1/FVC ratio under 0.7 are

  • GOLD Stage 1 FEV1 percent predicted ≥80% (mild)
  • GOLD Stage 2 80%, < FEV1 ≥50% (moderate)
  • GOLD Stage 3 50%, < FEV1 ≥30% (severe)
  • GOLD Stage 4 30%, < FEV1 very severe airflow limitation

Since 2011 the COPD Foundation and global researchers have recognized that many features of COPD exist before the development of airflow limitation.

In collaboration with experts from our Medical and Scientific Advisory Committee (MASAC), the COPD Foundation proposed a broader staging definition beyond those of GOLD with modified spirometry grades (SGO and SGU, SG 1-3) which are included in the COPD Pocket Consultant Guide App and published in 2019 here:

Spirometry Grades

We dedicated a Special Issue in November 2019 of Chronic Obstructive Pulmonary Diseases: Journal of the COPD Foundation to highlight the need to recognize the disease before the development of airflow limitation (FEV1/FVC ratio better than 0.7). Read from the editorial, "The Pressing Need to Redefine COPD" from this Special Issue to learn more.

Summary

COPD is not a "one-size-fits-all" disease. These levels, or stages, of COPD are just a broad guide to help you and your health care provider consider different types of treatment. Remember, all decisions must be based on your situation, your symptoms, and the total picture of you. There are several different factors that go into helping you and your health care provider understand what type of COPD you have and how best to treat it and manage it. Yes, COPD is progressive, and currently incurable. But it is very treatable and many people with COPD can live a long time, enjoying life, even with advanced disease.

Resources and Support

The COPD Foundation offers resources such as COPD360social, an online community where you can connect with patients, caregivers and health care providers and ask questions, share your experiences and receive and provide support.

Jenny says, “My doctor told me I have half of my lungs left. Exactly, what does this mean?”

Jenny’s doctor was likely referring to Jenny’s FEV1 which is 50% of the normal predicted. It’s not that one lung is doing all the work and her other lung is not doing anything. This actually means that in that first second of that long breath out, she blew out half as much air that a person of her age, height, and race with healthy lungs would blow.