Diseases that are progressive in nature are typically graded by stages, and these stages are often based on the severity of the disease or an analysis of symptoms. Chronic obstructive pulmonary disease is no different, and there are four main stages of the disease that your doctor may diagnose you with if you have COPD. However, the stage is not the only factor that will guide your treatment, nor is it the sole means of estimating how long or healthfully you may be able to live with COPD.

“There are a lot of different ways to define the stages of COPD,” says Philip Diaz, a pulmonary specialist at The Ohio State University Wexner Medical Center in Columbus, Ohio, “in part because it’s not a single disease.” He says different characteristics of the disease, your own genetics and the environmental factors you encounter are all aspects of how to approach classifying the stages of the disease.

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One of the more authoritative means of classifying cases of COPD comes from the Global Initiative for Chronic Obstructive Lung Disease (GOLD), an advocacy group for the awareness and management of COPD that was launched in 1997 in collaboration with the National Heart, Lung, and Blood Institute. GOLD publishes detailed guidelines about staging and grading COPD and how that can correlate to treatment protocols that are widely used in the treatment and management of COPD.

GOLD released updated guidelines in 2017, titled the ” Global Strategy for the Diagnosis, Management and Prevention of COPD,” which further refine its previous guidelines published in 2011 that classify COPD into four stages with additional grading detail of A, B, C or D status depending on several factors. This information is useful in helping doctors make decisions about treatment. “The goals of COPD assessment are to determine the level of airflow limitation, the impact of disease on the patient’s health status, and the risk of future events (such as exacerbations, hospital admissions, or death), in order to guide therapy,” the report states.

To determine the stage and grade of your COPD, in addition to assessing your symptoms, your doctor will administer a spirometry test to assess the amount of obstruction in your lungs. Dr. Umur Hatipoglu, director of the COPD Center at the Respiratory Institute at Cleveland Clinic, says these stage designations in COPD are “relatively arbitrary” but are “based on what’s called FEV1, Forced Exhaled Volume in one second predicted.” That means the volume of air that can be forcibly exhaled in one second.

Basically, this test measures how obstructed the air is as it’s leaving the lungs. Although spirometry is used to determine a patient’s prognosis, “in particular, mortality, meaning how long people are going to survive … is not the sole determinant of mortality,” Hatipoglu says.

The GOLD guidelines classify the stages on a 1 through 4 scale with GOLD 1 listed as mild COPD, which corresponds to an FEV1 score of 80 percent or greater than predicted. Hatipoglu says these predictions are based on age, gender, height, demographic comparison and the grading system that GOLD guidelines also include.

GOLD 2 or moderate COPD is diagnosed with an FEV1 score between 50 percent and 80 percent of predicted airflow. GOLD 3 or severe COPD is noted when FEV1 scores are 30 to 50 percent of what’s predicted. Finally, GOLD 4 or very severe COPD is diagnosed in patients with an FEV1 score at or below 30 percent of predicted volume.

“Although the staging gives us an idea of where the patient is, it is by no means the final statement on that patient’s prognosis or how well they’re going to do,” Hatipoglu says, adding, “the point I’m trying to make is that if patients hear that they are stage 3 or stage 4, they should not be immediately doom and gloom. They should have an open conversation with their physician about their prognosis and how things are going to shape up.”

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When staging a patient’s COPD, doctors should not only look at the results of the spirometry test, but look at other, “more sophisticated indices and other clinical markers such as how [far] the person can walk within a certain time period, specifically six minutes,” Hatipoglu says. Not surprisingly, that test is called the “six-minute walk.” Hatipoglu says signs of malnutrition and how severely short of breath a patient is at rest or during exertion are other ways of determining how far the disease has progressed.

“Exercise tolerance, weight, how short of breath you are, attitude and how you handle things all make a difference” in how your disease will progress and can be considered when determining the stage of your COPD, Diaz says. “We’re understanding more about prognosis, but it’s based on those factors,” he says.

Because the progression of COPD is dependent on more than just lung obstruction, Hatipoglu says, he tries to “avoid saying things like ‘end-stage’ or ‘terminal,'” even if a patient scores a GOLD 3 or GOLD 4 level on the spirometry test. “Any of those people can actually live reasonably satisfactory lives and improve their lives.”

He says staging can help your doctor determine the course of treatment you’ll take for COPD, and later-stage patients “should be considered for advanced therapies like lung transplantation,” but the number itself should not inspire undue fear and worry.

What’s more, “most pulmonologists will say that gradation of obstruction is not necessarily linked to management as strongly as people think,” Hatipoglu says. “For instance, in the last GOLD guidelines, they actually removed obstruction from the general paradigm of assessing patients with COPD. We still talk about it because, for example, lung transplant is considered for patients who have an FEV1 score of 20 percent or less, and lung volume reduction surgery is considered for patients who have an FEV1 score of less than 45 percent. So there’s still some value in the assessment. But when we look at patients, we actually look at their symptom burden and their risk for exacerbation. And we don’t necessarily look at obstruction grade and start prescribing medications for patients. The clinical presentation is more important than obstruction, and I think this has been recognized in the last guidelines.”

Diaz agrees. “I have a lot of people who’ve been diagnosed with later-stage COPD, and they’re concerned and scared. COPD can be awfully terrifying, particularly if you have a family member who’s had it. But the thing about these people with end-stage disease on oxygen: If they stop smoking, their prognosis is quite good.”

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The 2017 GOLD report also notes that a patient’s prognosis cannot be assessed solely on their FEV1 test results. Although these results can be predictive of how quickly your health could decline as the disease progresses, they don’t paint the full picture. Other factors such as genetics, environmental exposures and other risk factors you may encounter can speed up the progression of the disease or slow it down.

Bottom line: No matter how your COPD has been graded, don’t panic. Talk to your doctor about how to manage your symptoms, and follow his or her advice for mitigating risk factors that can contribute to a faster decline.

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What Are the Stages of COPD? originally appeared on usnews.com