Test Results Also Valuable in Inspiring Smoking Cessation
SEATTLE — Spirometry remains the only recognized method of definitively diagnosing chronic obstructive pulmonary disease, but nearly two-thirds of patients with a COPD diagnosis have never had the test, according to VA research.
DoD/VA guidelines recommend that providers evaluate any patient for COPD who has dyspnea, chronic cough or sputum production and a history of smoking. Many providers consider the presence of these factors as sufficient for diagnosis, but the VA/DoD and major international guidelines say that spirometry is necessary to make the diagnosis.
“Primary care providers by and large use symptoms as drivers of COPD diagnosis. If a patient has risk factors, receives therapy and improves, then they will diagnose COPD,” said David Au, MD, investigator in the VA’s Northwest Center of Excellence for health services research and development and associate professor of medicine and pharmacy at the University of Washington.
A 2006 analysis of 197,878 VHA patients with new diagnoses of COPD found that only 33.7% of them had spirometry at the VA in the previous year. Patients seen by pulmonologists had spirometry at more than three times the rate of others, and younger patients also were more likely to have the test, according to the research.1
More recent research has suggested the rate hasn’t improved much in the past eight years.
Au and his colleagues recently conducted qualitative studies of primary care physicians and found that “many physicians said they would continue to provide the same treatment, even if the patient had spirometry and was found to have air flow obstruction. They just don’t value the numbers.” The researchers found that spirometry remains undervalued because of a lack of understanding of the benefits of treating COPD and because there is no point-of-care measure for treating the disease as there is for frequently comorbid diseases such as diabetes mellitus and hypertension.2
Spirometry assesses three dimensions of lung function: forced expiratory volume in one second (FEV1) or how much air someone can exhale in one second after inhaling as deeply as possible; forced vitality capacity (FEV) or the total amount of air a patient can exhale after inhaling as deeply as possible, and the ratio of FEV1 to FVC. The VA/DoD guidelines consider someone with an FEV1/FVC ratio of .7 or less to have COPD.
If COPD is diagnosed, the amount of reduction in FEV1 a patient has relative to others his or her age is used as a factor in assessing the severity of the disease. According to the VA/DoD guidelines, an FEV1 that is 80% or more of normal value for a patient’s age indicates mild COPD, while value between 50% and 80% would indicate moderate disease, and those below 30% would characterize severe disease. Recent updates to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines encourage physicians to use those values in conjunction with symptoms and exacerbations to determine stage. 3
Relying on symptoms and patient reports results in a significant under-diagnosis of the disease, Au said. “Patients often mask their symptoms and they may be unaware of the subtle changes that occur in the early stages of the disease. The onset of COPD is insidious. Someone who could walk a mile can do just three-quarters of a mile, then half a mile. By the time they tell a physician that they are winded when they can only walk a couple of blocks, you’ve lost a lot of ground,” he noted.
Common comorbidities such as congestive heart failure, obesity and deconditioning can also lead to missed diagnoses or misdiagnoses. “If any provider makes a diagnosis of COPD without spirometry, they are wrong about half of the time,” Au noted.
Getting that diagnosis right — and early — can substantially reduce healthcare costs. Low FEV1 measures, associated with more severe disease, are inversely related to the cost of COPD management, according to a recent study of 3,263 patients done at the Cincinnati VA Medical Center. The researchers also found that hospitalizations accounted for 87% of COPD costs. As several medications are now available that can reduce exacerbations, early diagnosis and treatment can reduce the impact on quality of life and total healthcare costs. 4
The value of spirometry extends beyond definitive diagnosis of COPD. “Cessation of smoking is the only treatment unequivocally shown to improve lung function and mortality,” Au pointed out. “Physicians often think that spirometry can’t help get patients to quit smoking, but it can. It’s all in how we frame the results.”
A study in the British Medical Journal found that giving patients their “lung age” or the age of an average healthy person who would have similar results on spirometry more than doubled the number of smokers who quit compared with those who were give their FEV1 score. In the study, 13.6% of the “lung age” group stopped smoking compared with 6.4% of those given spirometry measures. 5
“If you say to a 45 year old, ‘You have the lungs of a 75 year old,’ that has meaning to them,” Au said. Saying ‘You have 50% of predicted lung volume.’ doesn’t mean anything to most people.” In the study, the lung-age information led to smoking cessation in patients who had normal lung function as well as those with impaired function.
- Lee TA, Bartle B, Weiss KB. Spirometry use in clinical practice following diagnosis of COPD. Chest. 2006 Jun;129(6):1509-15.
- Joo MJ, Sharp LK, Au DH, Lee TA, Fitzgibbon ML. Use of spirometry in the diagnosis of COPD: a qualitative study in primary care. COPD. 2013 Aug;10(4):444-9.
- Global Initiative for Chronic Obstructive Lung Disease. Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease. January 2014.
- Parkes G, Greenhalgh T, Griffin M, Dent R. Effect on smoking quit rate of telling patients their lung age: the Step2quit randomised controlled trial. BMJ. 2008 Mar 15;336(7644):598-600.