Smoking and Spirometry                           By: Paul Enright, M.D.

Fishing for Answers

What Does it Take to Get a Smoker to Quit?

My old friend, Bill Wood, game me my first fishing rod and reel and taught me how to catch reef fish along Kauai's north shore 10 years ago. When we first met, Bill was a 50-year-old gray-haired, chain-smoking banker from New Mexico with a potbelly and hypertension. He had just quit his angina-inducing A mainland job and moved to the A garden island to regain health and happiness.

He was becoming a happy native, with a dark tan, a ponytail and well-defined muscles from working outdoors every day in landscape maintenance. But he still had a chronic cough from smoking a pack a day. I never bothered my close friend about smoking, but he knew that I was a pulmonary physician, so he didn't smoke in our home, and he asked me for some nicotine patches.


When I arrived in Kauai for a Christmas vacation visit last year, I was shocked to see a green tank with nasal prongs in Bill's living room. I learned that he had spent Thanksgiving week hospitalized with respiratory failure and was now too short of breath to return to work. Bill seemed depressed and asked me to go with him for a follow-up visit with his primary care physician in Kilauea so that I could help translate what had happened.

It was two days before Christmas but 80 degrees and sunny. Bill grumbled about having to wait 10 minutes for Doc Wilson to return from lunch. Doc asked my friend if the bupropion had helped to stop the cravings and congratulated him for not smoking since the hospital physicians had attempted to intubate him a month ago. I tried to hide my surprise and chagrin when I read Bill's admission ABGs and X-ray reports. I immediately felt very guilty that I had not helped him quit smoking 10 years ago.

A nurse carried a small spirometer into the exam room and coached Bill to blow forcefully into the white trumpet several times. He had never seen a spirometer before and complained that all that effort was either going to make him puke, pass out or both. Sure enough, when she returned with the printed report, the flow-volume curve looked like a rat's tail and his FEV1 was less than 50% of the value predicted by Ron Knudson's equations. At least Bill' pulse oximetry reading showed 94 percent saturation, so he didn't need the oxygen at home anymore.


Over Christmas, I told Bill that he was one of the unlucky one of five smokers whose lungs are susceptible to develop emphysema. His lung function would improve a little bit as he continued to recover from his episode of pneumonia, but he would probably need to hire a younger co-worker to handle the heavy landscaping work. He didn't like my advice that he should get a flu shot every fall, but he now had a better excuse to avoid small children with viruses. He assured me that he would never start smoking again. I hoped that he would keep taking the bupropion for several months longer than the Physician's Desk Reference recommendation.

I drew a graph for Bill on the back of a Hanalei Bay restaurant menu. (See graph). Susceptible smokers arerapid fallers who lost one-half to one liter of lung function (FEV1) every decade. The Lung Health Study1 showed that susceptible smokers with airways obstruction (a low FEV1/FVC) who are helped to stop smoking quickly experience a small increase in lung function and then their subsequent rate of decline becomes that of a never smoker (about 0.3 liters per decade).

Graph:lung function over time with/without smoking

Susceptible smokers with airways obstruction who stop smoking experience a small increase in lung function, and then their subsequent rate of decline becomes that of a never smokers (graph/courtesy Paul Enright, M.D.

Ten years ago, Bill's FEV1 had fallen below the lower limit of the normal range (about 80 percent predicted). If I had tested his lung function then and showed him the graph, he would have been more likely to take smoking cessation seriously. Had he quit smoking then, he would still have plenty of reserve lung function, would not have developed respiratory failure when he caught pneumonia in November, and would not now be disabled by shortness of breath.

Photo of author, Dr. Paul EnrightPhoto of Bill Wood

Dr. Paul Enright (left) and his fishing buddy, Bill Wood, caught a moray eel off the shore of Kauai. During a recent visit, Dr. Enright counseled his friend about the importance of lung function testing for smokers. Photos/courtesy Paul Enright, M.D.


COPD is now the fourth leading cause of death in the United States, killing 100,000 every year.2 About 16 million smokers have the diagnosis, about 550,000 annually are hospitalized with an exacerbation of their COPD, and $13 billion is spent on their health care.3

Since everyone knows that smoking is bad for their health, why don't they quit?I think that many people simply think that they will beat the odds, just like the millions who think that they will win the lottery. If they were faced with some evidence that they were not one of the lucky smokers, I believe they would be more likely to make an effort (or several efforts) to quit.

Other experts disagree with me. They argue that checking smokers for airways obstruction (or for smoking-related subclinical artery disease) is a waste of time and money and might actually be counter-productive because about 80 percent of the results will come back normal, and those smokers with normal results will feel justified in continued smoking. Therefore, they suggest all patients who smoke cigarettes simply should be told to quit and referred to a good local smoking cessation program.4


How many smokers have respiratory symptoms, and how many have airways obstruction, but don't know it? About every 20 years, the NIH sponsors a very large population-based survey of the health of Americans, called the National Health and Nutrition Examination Survey (NHANES). The most recent survey included spirometry, smoking status and respiratory symptoms. The NHANES III spirometry results for healthy persons were published last year5 and will become the single standard set of spirometry reference equations for North American (replacing the Morris, Knudson and Crapo prediction equations). An even more recent analysis of the results from the smokers, commissioned by the National Lung Health Education Program (NLHEP), was just published.6

Airway obstruction was defined as FEV1/FEV6 and FEV1 both below the lower limit of the normal range. (The FEF25-75% and other misleading spirometry parameter were not used.) An estimated 15 million smokers over age 45 have airways obstruction, like my friend Bill. About 9 million of them have a respiratory symptom, like chronic cough, phlegm, wheezing or shortness of breath on exertion. Those with a respiratory symptom are much more likely to have abnormal spirometry than those without symptoms (26 percent vs. 10 percent). Women are more likely to be affected than men. On the other hand, only about 5 percent of smokers below the age of 45 have airways obstruction (similar to the prevalence of asthma in adults).


Based on these results, the NLHEP consensus document recommends that primary care practitioners perform spirometry testing for all of their patients over age 44 who are current or recent smokers and who have a respiratory symptom.6

If all of these smokers saw their PCP at least once during the next few years, and all the PCP's actually followed these recommendations, the total expenses of such testing might be more than 100 million dollars.

What is the cost to benefit ratio? How many of the patients will actually be prompted to quit when faced with their abnormal spirometry results? How many would have quit soon anyway without the spirometry testing? How many of those with normal spirometry will be even less likely to quit? What percentage of the spirometry tests done in the PCP's office will be false positive and false negative because of poor quality of the instrument or the coaching?

The NLHEP document attempts to answer these questions, but some cannot be answered until office spirometers that meet the NLHEP specifications are manufactured and validated in real-world PCP outpatient settings. These new office spirometers will be as accurate as diagnostic spirometers, as specified by the American Thoracic Society.7 However, NLHEP-type office spirometers will be small, battery-powered, relatively inexpensive, and the patients will only need to exhale for six seconds. The spirometer will have extensive maneuver quality checks, will report only the FEV1, FEV6, and the FEV1/FEV6 ratio, will provide an interpretation only if the test session quality is good, and flow-volume graphs and printouts are optional.


What about reimbursement for spirometry? NLHEP does not recommend screening spirometry (which cannot be reimbursed). Spirometry testing of a smoking patient with a respiratory symptom is a well-recognized indication, and CPT codes apply. The appropriate CPT code is 94010 or 94160 with a 1995 RVU of 0.17. But some folks use the CPT code 94375 for spirometry with a flow-volume loop, or pre- and post-bronchodilator spirometry CPD code 94060 with a RVU of 0.31.

One of my mentors, Tom Petty, M.D. has suggested for decades that the FEV1 should be a vital sign, without a separate charge,8 but not many PCP's follow his advice. Medicare currently pays about $20 for spirometry, and third-party insurers pay up to $60 for the test when indicated.

I believe that in a few years, after the new generation of office spirometers are fully developed, validated and have gained wide acceptance, economic studies will show that they cost less and take less time to complete a test, when compared to diagnostic spirometry. Perhaps a new CPT code (with less reimbursement) will then be developed for office spirometry.

I look forward to the day when Doc Wilson and other PCP's routinely take 10 minutes extra to perform office spirometry for 50-year-old smokers with a cough like my friend Bill 10 years ago. If they have airways obstruction, the doctor will explain that they are not one of the lucky smokers beating the odds, set a quit date and recommend the most effective smoking cessation program in town.

Then we will have fewer hard-working, fun-loving, but breathless friends like Bill in their 60s with moth-eaten lungs, green tanks, and 50 percent five-year survival rates.


1. Anthonisen NR, Connett JE, Kiley JP, et al. Effects of smoking intervention and the use of an inhaled anticholinergic bronchodilator on the rate of decline of FEV1: the Lung Health Study. JAMA 1994;272:1497-1505.

2. Morbidity and Mortality. Chartbook on Cardiovascular, Lung, and Blood Diseases. National Heart, Lung and Blood Institute. 1998.

3. Benson V, Marano MA. Current estimates from the 1993 National Health Interview Survey, DHHS Pub. #PHS 95-1518.

4. Badgett RG, Tanaka DJ. Is screening for COPD justified? Prev Med 1997;26:466-472.

5. Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general U.S. population. Am J Respir Crit Care Med 1999;159:179-187.

6. Ferguson GT, Enright PL, Buist AS, Higgins MW. Office spirometry for lung health assessment in adults. A consensus statement from the National Lung Health Education Program. Chest 2000:117:1146-1161.

7. American Thoracic Society. Standardization of spirometry: 1994 update. Am J Resp Crit Care Med 1995;152:1107-1136.

8. Petty TL, Weinmann GG. Building a national strategy for the prevention and management of and research in chronic obstructive pulmonary disease. NHLBI workshop summary. JAMA 1997;277:246-253.

Dr. Paul L. Enright is a Research Associate Professor of Medicine at the University of Arizona, Tucson. He can be reached at

Advance for Managers of Respiratory Care                  May, 2000 9:34-37.