Chronic obstructive pulmonary disease (COPD) presents a paradox, as it's both underdiagnosed and overdiagnosed.
Roughly 10% of adults ages 40 years and older show evidence of persistent airflow obstruction with spirometry, but just 20% to 30% of those individuals have been diagnosed with COPD, according to a review article published in 2018 in the American Journal of Respiratory and Critical Care Medicine. Meanwhile, other studies cited in the review show that one-third to one-half of patients in the primary care setting have been incorrectly told that they have COPD.
Both diagnostic pitfalls pose problems, said Samir Gupta, MD, MSc, a pulmonologist at St. Michael's Hospital and an associate professor in the department of medicine at the University of Toronto. While underdiagnosis prevents people from getting the medications and other treatment that could ease symptoms, the impact of misdiagnosis shouldn't be overlooked, he said.
Along with missing the correct explanation for their symptoms, patients might also be exposed to the costs and side effects of unnecessary medication, along with the consequences of living with a chronic disease, which can influence everything from insurance coverage to self-perception, Dr. Gupta said. “There is the impact of a label that you can't dismiss for some people.”
Various factors might underpin these diagnostic misses, said Dr. Gupta and other COPD experts. Physicians might too often rely on symptoms alone without testing for lung function with spirometry, required to confirm diagnosis. Or they might miss symptoms, either because they don't ask their high-risk patients or because those patients don't disclose them.
In some cases, physicians might not feel the same degree of urgency to flag cases of COPD earlier as they would to, for instance, identify and treat high blood pressure, said MeiLan Han, MD, MS, chief of the division of pulmonary and critical care at the University of Michigan in Ann Arbor.
“I think there is a sense of nihilism on the part of primary care physicians,” Dr. Han said. “The issue is that clinicians don't think that the medications make a difference. But they do. They do prevent patients from ending up in the hospital and they also, in appropriate patients, can reduce the risk of death.”
Flagging cases sooner
In the U.S., about 6% of adults are diagnosed with COPD, an umbrella term that covers the conditions of emphysema and chronic bronchitis. While the progressive disease commonly is associated with smoking, as many as one-third of patients have never used tobacco, according to the National Institutes of Health.
A recent review of COPD and health disparities, published in 2021 in Current Pulmonology Reports, found that women are more than three times as likely as men to have severe disease at the time of diagnosis. Also, Black patients experience higher rates of hospitalization and worse COPD-related quality of life than White patients. (See this article's sidebar for more research on potential disparities.)
At this point, routine screening is not recommended in middle-age and older adults. This spring, the U.S. Preventive Services Task Force reaffirmed its 2016 statement that COPD screening, including spirometry, should not be conducted in asymptomatic adults. The Task Force found inadequate direct evidence that screening could reduce mortality or improve health-related quality of life, according to the statement, published May 10 by JAMA.
An alternative approach, advocated by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) in its 2022 report on diagnosis and treatment, is what's described as active case finding. Rather than routine screening, spirometry should be considered in individuals with symptoms or risk factors, the report recommended. For instance, in adults with recurrent chest infections or greater than 20 pack-years of smoking, “the diagnostic yield for COPD is relatively high and spirometry should be considered as a method for early case finding,” the GOLD authors wrote.
Physicians should have a “high index of suspicion” when encountering a patient in their 40s or older with a smoking history, said Nicola Hanania, MD, MS, FACP, a professor of medicine and director of the Airways Clinical Research Center at Baylor College of Medicine in Houston. Due to stigma, patients might not volunteer symptoms, including a nagging smoker's cough, he said.
Physicians can learn a lot with a few questions during a routine physical exam, Dr. Hanania said. Ask patients how often they cough, and if they cough anything up when they do, he suggested. Also, try to gain a sense of whether they have noticed more fatigue or a decline in activity, which they might have erroneously attributed to getting older.
“The right question is not, ‘How are you feeling?’” Dr. Hanania said. “It's ‘How much are you doing?’ And ‘How much are you doing compared with a year ago?’”
Dr. Gupta reiterated this point, stressing that physicians should be proactive about watching out for symptoms in high-risk patients. Along with a smoking history, other potential indicators of COPD include occupational exposures, recurrent wheezing, and a family history, according to the GOLD 2022 report.
“Part of the issue is pulling it out of the patient,” Dr. Gupta said. “Don't assume that the patient will share their complaints—instead, ensure that they don't have them.”
To date, there's no “good, validated questionnaire” for COPD screening, Dr. Gupta said. But physicians might still find it useful to ask patients with worrisome symptoms to fill one out to gain further insights, he said.
Some tools he cited included the COPD Diagnostic Questionnaire, CAPTURE™ (COPD Assessment in Primary Care To Identify Undiagnosed Respiratory Disease and Exacerbation Risk), and the Undiagnosed COPD and Asthma Population Questionnaire (UCAP-Q). If results warrant testing, then the patient can be referred for spirometry, he said.
By all accounts, though, spirometry remains woefully underused. One study published in CHEST in 2014 involving 491,754 Canadians newly diagnosed with COPD found that only 35.9% got spirometry within a year of their diagnosis.
In the primary care setting, there are more barriers than enablers to spirometry, according to a systematic review Dr. Gupta helped author that looked at 18 studies and was published in April 2022 in CHEST. These included lack of clinician knowledge about its usefulness, insufficient skills to perform the test in the office or interpret its results, and lack of belief that the findings would influence treatment or patient outcomes. Enablers included a belief that the results might help frame a discussion about smoking cessation.
For time-pressed primary care physicians, it can be difficult to incorporate spirometry into the workflow of the practice, said Gerard J. Criner, MD, FACP, chair and professor of thoracic medicine and surgery at Temple University's Lewis Katz School of Medicine in Philadelphia, as well as a member of the GOLD Science Committee. One option to avoid referring patients elsewhere is to train a staffer, such as a medical assistant, to perform the test, he said.
But patients shouldn't be prescribed medications without confirming a tentative diagnosis with spirometry, Dr. Criner said. “If they don't have the disease and you treat them, you might be missing another disease that they do have, such as heart disease or something else,” he said.
When patients do have COPD, failure to get pulmonary function testing might impact their trajectory, according to a study involving nearly 69,000 Canadian adults with diagnosed COPD. Four out of 10 adults, 41.2%, got spirometry around the time of diagnosis. (The study authors note that while it's unknown if all of the study patients had COPD, they were diagnosed with a previously validated case definition with a specificity of 95%.) Patients who got pulmonary function testing were 9% less likely to be hospitalized with COPD or to die of any cause versus those who did not, according to the findings, published 2017 in the Canadian Medical Association Journal.
“If you know what the disease is and you know the severity of the disease, then you can treat it better,” said study author Andrea Gershon, MD, MSc, a pulmonologist and professor of medicine at the University of Toronto. “We actually showed that people who received pulmonary function testing were on more medications than people who didn't receive pulmonary function testing.”
A differential diagnosis
Another diagnostic challenge is sorting out which patients with shortness of breath and other symptoms have asthma rather than COPD, said Dr. Han, who also is a member of the GOLD Science Committee. Some adults live with both conditions. But some factors point more to a diagnosis of asthma, such as the onset of symptoms earlier in life, underlying allergies, and a variability in symptoms, Dr. Han said.
“Whereas patients with COPD, it's not this day-to-day variation,” she said. “It's, ‘‘Every time I go to exercise, I'm short of breath.’”
The 2022 GOLD report lists other conditions that might be considered as part of a differential diagnosis, including congestive heart failure and tuberculosis. The authors noted that patients with COPD often have other conditions that also must be treated, ranging from cardiovascular disease and metabolic syndrome to depression and anxiety.
Spirometry is required not just to confirm the COPD diagnosis but also to determine staging and prognosis, given that the lower the lung function is, the higher the risk for exacerbations and mortality, Dr. Hanania said. Bronchodilators and other COPD medications have been shown to reduce symptoms and improve quality of life, including the ability to stay active, he said.
Two recent studies have shown that prescribing multiple medications in patients with more severe COPD, based on symptoms and a history of exacerbations, might also reduce mortality, Dr. Hanania said. “There is some excitement in the air,” he said, cautioning that these findings were the result of secondary analyses of these studies and are therefore not definitive.
In the meantime, getting the diagnosis right as early as possible also enables physicians to initiate frank discussions with patients about staying active, improving nutrition, and quitting smoking, physicians said.
One frequently cited study, published in 2008 in the British Medical Journal, found that providing patients a window into their own lung age—how their spirometry findings compare with the average healthy individual—can be influential for smoking cessation. By one year later, 13.6% of those who had gotten the lung assessment had quit versus 6.4% in the control group.
Too often, patients with undiagnosed COPD hide in plain sight, reluctant to share their symptoms and related limitations amid embarrassment about smoking, past or present, Dr. Gershon said. “I think the stigma is a big issue,” she said. “Heart disease is related to smoking and cancer is related to smoking, and we don't blame those patients.”
Dr. Gershon was involved with an analysis of Canadian data, published in 2011 in The Lancet, finding that one in four people will be diagnosed with COPD over the course of their lifetime. Primary care physicians shoulder a daunting load as they try to address all their patients' medical needs, she said.
“But I think we all have to be vigilant for this disease that's less documented, underrecognized, maybe a little misunderstood,” Dr. Gershon said. “We have to be vigilant for it because it's this deadly disease, and it's a huge burden on people in the health care system.”