Stages of COPD
One of the most common questions asked by people with COPD is, “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.
Until recently, the four stages of COPD have been based on one spirometry / lung function test number, the FEV1. While it’s important to have a spirometry test and know your FEV1, that doesn’t tell us everything. In fact, often your lung function numbers are not a good predictor of your symptoms or what will happen with your COPD 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, 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 is a FEV1?
When you take a spirometry or lung function test, 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 measures how much air you blew out in the very first second of that long breath out (exhalation). This is the FEV1, your Forced Expiratory Volume in the first second. It then takes that number and compares it to the amount of air that a person your age, your height, and your race, with normal, healthy lungs would blow out in that first second.
FEV1 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 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 attending pulmonary rehabilitation and regular activity.
- 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 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 FEV1, these differences in when you oxygen level is low (if at all) can determine how things will be over the next few years.
- 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 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, such as heart disease, diabetes, anxiety, or depression?
- Treating your other conditions and getting them under control can improve what is happening with your COPD no matter what your FEV1 is.
All these factors can have a significant effect 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.
COPD Foundation Spirometry Grades are based on the ratio of FEV1 to FVC, Forced Vital Capacity (the amount of air you blow out in that first second divided into the amount of air you blow out in that whole long exhalation).
- SG 0 Normal – does not rule out emphysema, chronic bronchitis, asthma or the risk of developing COPD
- SG 1 Mild: FEV1/FVC ratio < 0.7 | FEV1 >=60% normal predicted
- SG 2 Moderate: FEV1/FVC ratio < 0.7 | FEV1 30 – 59% normal predicted
- SG 3 Severe: FEV1/FVC ratio < 0.7 | FEV1 <30% normal predicted
- SG U Undefined: may indicate a restrictive disease, muscle weakness or other disorder
These levels, or stages, of COPD are just a broad guide to help you and your healthcare provider consider different types of treatment. Remember, all decisions must be based on your situation, your symptoms, and the total picture of you.
COPD is not a “one-size-fits-all” disease. There are several different factors that go into helping you and your healthcare 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.