Chronic obstructive pulmonary disease (COPD) is a group of lung diseases that progress over time. COPD is most common in smokers and people over the age of 40. It’s estimated that about 174 million people have COPD, and more than 3 million people around the world die from it each year.

People with COPD often have trouble breathing, a persistent cough, and shortness of breath. COPD can be subdivided into stages or grades, depending on how far it has progressed.

In its early stages, COPD is barely noticeable, but it gets worse over time unless you get proper treatment. The earlier you catch it, the better your outlook is.

Keep reading to learn about the four stages of COPD. We’ll break down the symptoms you can expect at each stage and potential treatment options.

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) is a program started by the National Heart, Lung, and Blood Institute and World Health Organization. Countries around the world use its guidelines and recommendations for diagnosing and treating COPD.

The GOLD system previously classified COPD from stages 1 to 4 solely based on your lung capacity measured by a spirometry test. But the newest GOLD guidelines combine your spirometry results with subjective measures of your symptom severity to determine your level of risk based on their ABCD rubric.

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The GOLD COPD grading system uses symptoms and exacerbations to grade the severity of COPD. This helps your provider determine which medications to use to help control COPD. Wenzdai Figueroa.

A spirometer test involves exhaling into a machine called a spirometer. The machine measures how hard and quickly you can exhale.

Your doctor will examine two numbers: your force vital capacity (FVC) and your force expiratory volume in one second (FEV1). Your FVC is the total amount of air you can breathe out and FEV1 is the amount you breathe out in one second. A ratio of your FEV1/FVC needs to be less than 0.7 for a diagnosis of COPD.

Your doctor will grade your spirometry results from grade 1 (least severe) to grade 4 (most severe). These grades correlate with stage 1 to stage 4 COPD in the old system.

Your healthcare provider will determine the severity of your symptoms using either the British Medical Research Council (mMRC) questionnaire or the COPD Assessment Test (CAT).

Stage 1 COPD is considered mild. At this stage, you may not be aware that you have anything wrong with your lung function. Your doctor will assign you with grade 1 COPD if your FEV1 is between 80 and 100 percent of your predicted value.

Symptoms

If you score grade 1 on your spirometry test, you may not have any noticeable symptoms. If you do have symptoms, you may develop a cough and increased mucus production. You may mistake the early stages of COPD for the flu.

Treatment

With stage 1 COPD, your doctor may recommend a bronchodilator medication to open up the airways in your lungs. These medications are usually taken through an inhaler or nebulizer.

Your doctor may also recommend getting flu and pneumonia vaccines to prevent illnesses that may worsen your respiratory symptoms.

Changing lifestyle habits that led to the development of COPD can potentially help slow the progression of your COPD. Most people with COPD have a history of smoking. Quitting smoking and avoiding secondhand smoke are two of the most important things you can to improve the outlook of your disease.

Your COPD is considered to be stage 2 when your FEV1 drops to 50 to 79 percent of your predicted value.

Symptoms

During stage 2, your symptoms worsen from stage 1. Your coughing and mucus production may become more severe, and you may experience shortness of breath when walking or exercising. Typically, it’s in this stage that people realize that something is wrong and seek medical attention from a doctor.

Treatment

You may be given bronchodilator medication to increase airflow to your lungs.

Your doctor may recommend pulmonary rehabilitation, which is a program designed to increase your awareness about your condition. It’s usually offered as a group class where you’ll learn how to better manage your condition.

If you have a flare-up of symptoms, you may need to take steroids or oxygen.

By the time you reach stage 3, COPD is considered severe, and your forced expiratory volume is between 30 to 50 percent of your predicted value. You may have trouble catching your breath doing household chores and may not be able to leave your house.

Symptoms

By stage 3, you may get more frequent flare-ups, and your shortness of breath and coughing will get worse. You will likely find you get tired easier than before.

Other potential symptoms can include:

Treatment

The treatment options for stage 3 COPD are similar to stage 2. You’re more likely to need to go on oxygen at this stage.

Stage 4 is considered very severe. Your forced expiratory volume is less than 30 percent of your normal value, and your blood oxygen levels will be low. You’re at risk of developing heart or lung failure.

Symptoms

By stage 4, you’ll likely have frequent flare-ups that can be potentially fatal. You may have trouble breathing even when you’re resting.

Treatment

Treatment options during stage 4 are similar to the previous stages. Your doctor may also recommend lung surgery to improve breathing. Surgical options include:

A grade 4 score on your spirometry test is the highest grade you can receive. This category is also sometimes referred to as end-stage COPD.

For many people at this stage, quality of life is usually fairly low, and symptom flare-ups can be fatal.

Having COPD lowers your life expectancy. However, the amount that it affects your life expectancy depends on many factors, such as how far your COPD has progressed and whether you quit smoking or change the lifestyle habits that lead to COPD.

An older 2009 study found that COPD led to a small reduction in lifespan for people who have never smoked, but a larger lifespan decrease for people who currently smoke or smoked in the past.

According to the researchers, a 65-year-old man who smokes would lose 3.5 years from their life expectancy for smoking, plus the following values for having COPD:

  • Stage 1: 0.3 years
  • Stage 2: 2.2 years
  • Stage 3 or 4: 5.8 years

For former smokers, the reductions are:

  • Stage 1: 1.4 years
  • Stage 2, 3, or 4: 5.6 years

For somebody who never smoked, the reductions are:

  • Stage 2: 0.7 years
  • Stage 3 or 4: 1.3 years

In a 2017 study, researchers followed a group of long-term smokers with COPD for 5 years. They found that participants who had died before a 5-year follow-up had a longer average smoking time and a lower prevalence of quitting smoking. The researchers concluded that smoking time may be related to COPD mortality rate, and quitting smoking has the largest potential to influence COPD outlook.

COPD can’t be reversed, and it’s currently not possible to stop the progression of your COPD completely. You can help you slow the progression of COPD as much as possible by working with your doctor and following a proper treatment program.

No matter how far along your COPD has progressed, it’s important to change the lifestyle habits that caused your COPD in the first place. The most important thing you can do is quit smoking. If you don’t quit, you’ll continue to damage your lungs, and your COPD will progress quicker than it otherwise would.

Eating a low-carb diet filled with plenty of vegetables, healthy fats, protein, and unprocessed foods may help you manage your symptoms and maintain a healthy weight. Eating foods that cause bloating, like apricots or peaches, may exacerbate breathing problems in some people.

Regular exercise may help decrease symptoms of COPD by strengthening your respiratory muscles and improving your cardiovascular health.

COPD used to be categorized from stage 1 to stage 4 depending on how much your lung function had decreased. Now, doctors combine the results of a lung function test with subjective measures of symptom severity to determine your COPD risk.

Quitting smoking is the most important thing you can do after being diagnosed with COPD to improve your life expectancy and outlook.