Office spirometry test alone is not enough to diagnose COPD
DEAR DR. ROACH: I am a healthy 70-year-old woman. The only prescription medication I take is for dry eyes. I recently visited my new primary physician for the first time, and she had me do a breathing test, where I exhaled into a tube to measure airflow. I was told to breathe deeply and exhale completely into the tube three times in succession. It took less than a minute to complete. It is apparently a routine test she orders for new patients.
She then told me I have COPD, on the basis of that test alone. She asked if I had ever smoked or been exposed to secondhand smoke. That was her only question -- coughing or shortness of breath was never mentioned. I have never smoked, but my father was a smoker when I was growing up. I actually do have a slightly productive cough most mornings. I probably walk about 10 miles a week, and I do notice some shortness of breath on long uphill sections, though I can walk briskly in level areas for miles with no problem.
She said it is not advanced enough to require an inhaler at this time. I am bothered by this very easy “diagnosis” on the basis of one simple test. I wonder if I should ask to be referred to a pulmonologist for a more thorough evaluation. -- O.P.
ANSWER: The test your doctor performed is called office spirometry, and it is useful for monitoring known pulmonary diseases, especially COPD and asthma. However, by itself, it is inadequate to make the diagnosis of COPD, which I am not sure you have.
The diagnosis of COPD is made in people with persistent respiratory symptoms, usually shortness of breath or coughing. Spirometry will usually show obstruction to airflow. Formal pulmonary function testing, which is an extensive process taking an hour or so with a skilled and experienced technician, is ideal for determining severity.
The problem with getting a breathing test in someone who has no significant symptoms is that you can find someone whose test results are at or just below the lower limit of normal, and the diagnosis is unclear. The prognosis for people with mild airway obstruction but with no symptoms of COPD is much better than for people with COPD and who continue to smoke. For this reason, using spirometry as a screening test for everyone is not recommended.
Without knowing the exact results of your spirometry, I suspect you do not have COPD, given your absence of smoking and your extremely mild symptoms. A comprehensive exam by a pulmonologist would be definitive and may help you be less anxious about the results you have now.
DEAR DR. ROACH: My wife is wondering whether vitamin supplements such as the AREDS-2 formulation would help lower the chance of developing macular degeneration. Both her parents suffered from that. -- R.C.
ANSWER: The AREDS-2 vitamins are used in people with dry age-related macular degeneration to slow progression of the disease. Although it would make sense that the same treatment that slows existing disease might prevent it from coming on in the first place, the trials that have been done to test whether that is true were unable to show a benefit from the vitamin formulation. Only people with moderate disease showed benefit. The benefit was not huge: 11 people would need to be treated for seven years to prevent progression in one person.
I suspect there is some slight benefit, but it is so small that even moderately large trials are unable to prove it.