September 16th, 2009
Did you know that elite swimmers have a higher prevalence of asthma than other athletes? Surprisingly, this fact was only confirmed in a study relatively recently. Chlorine was an obvious candidate to explain this finding and over the last decade, evidence has been mounting to suggest that water chlorination does indeed lead to an increased risk of developing not only asthma, but allergies as well.
Initially, the problem was blamed on trichloramine, the gas that gives indoor pools their characteristic smell. Once it was discovered that outdoor pool exposure was as bad as indoor pool exposure, then the focus shifted to chlorine products in the water or vapors present around the water surface.
A recent study from Belgium published in the journal Pediatrics looked at three groups of adolescents, two of which had utilized only chlorinated pools and one of which utilized a pool decontaminated by means of a copper/silver ionizer. I read the study in detail and it is very complicated and has some potential holes. Nevertheless, I think it does clearly demonstrate that kids who spend a large amount of time in a chlorinated pool are more likely to develop asthma and/or respiratory symptoms of cough and shortness of breath and are more likely to develop allergies.
Given that there are other means of decontaminating pools such as salt water or ionizers, regulatory bodies should reconsider the appropriateness of chlorine as the standard pool decontaminant.
Dr. O
May 11th, 2009
During Spring, many people find that their asthma gets worse. They experience tightness in their chest, shortness of breath, and an increased cough. Albuterol use increases. Patients experience this secondary to the increased tree and grass pollen.
If you think your asthma may be poorly controlled, go to www.asthmacontrol.com and take the Asthma Control Test. There are 5 questions with a max point total of 5, minimum of 0. If your total score is less than 20 then your asthma may not be controlled and you should call your doctor for further evaluation. You can print off your test and bring it with you to your appointment. This saves time and may provide quicker treatment which could result in less ER visits and less aggressive therapies.
Dr. Norvell
January 22nd, 2009
Most wheezing in young children is due to viral infection of the airways, often termed bronchiolitis. A common cause would be Respiratory Syncitial Virus which you may have heard of as RSV. Essentially all wheezing below the age of 3 and most wheezing between the ages of 3 and 6 falls into this category. The wheezing produced by these infections results from damage and swelling of the airways as a direct result of the viral infection. Traditionally, kids with bad wheezing from such infections have been given steroids to try and reduce the swelling and inflammation.
This week’s New England Journal of Medicine has two interesting studies examining this practice. In the first kids with viral induced wheezing who were sick enough to be hospitalized were randomly given either prednisone or placebo. As it turns out there was no difference in the length of hospital stay or any other outcome between the two groups. In the second study, kids between the ages of 1 and 6 who had strictly viral induced wheezing were given inhaled steroids at the start of an upper respiratory infection to try and prevent wheezing. In this study, inhaled steroids were no better than placebo at preventing viral induced wheezing.
These studies will likely lead to a significant change in the treatment of viral induced wheezing. I would like to stress that these studies do not examine the effects of steroids on asthma or viral induced asthma exacerbations.
January 15th, 2009
A while back, the FDA decided to look into the issue of mood disturbance and drugs like Singulair. Through an extensive review of over 20000 patients, the data show no increase in depression or suicide in patients treated with Singulair. They are still reviewing the data to see if there is a link between Singulair and behavioral issues in kids. My sense is that this will be ok as well, but we’ll await the findings of their review. For now, If you’re on Singulair for control of asthma or allergies, you should feel safe to continue these medications
December 15th, 2008
A few weeks ago, I posted on the recent meta-analysis examining the safety of long acting beta-agonists, LABAs. Going by the names salmeterol (Serevent) and formoterol (Fordil), these medications are components of Advair and Symbicort, which also contain inhaled corticosteroids. The FDA recently convened a special advisory panel regarding the safety of these agents, and, fortunately, there were prominent members of the asthma community to advise them along the way. Following the best available evidence and expert opinion, the panel reaffirmed that combination therapy is the preferred choice for adults and children with persistent asthma.
Additionally, they said that LABAs should not be used in isolation, without the addition of an inhaled steroid. For anyone familiar with the literature and with these medications, this is a glaringly obvious conclusion. The scary part is that the FDA had to convene a special panel to resolve internal disagreements regarding the use of these medications. Thanks to those members of the AAP, ATS, and AAAAI who aided in this important decision.
December 10th, 2008
Asthma is classified as an obstructive lung disease. This means asthmatics have difficulty getting air out or exhaling. This is caused by narrowing of the airways and manifests as wheezing or prolonged exhalation. The ability to move air in and out can be measured by a simple test called spirometry. Spirometry is an integral part of the management of asthma. It is such an important test, that everyone with asthma should do it at least once and most asthmatics need it more often.
The reason this is so important is twofold. First, there is a huge disconnect between how people perceive their asthma severity and the reality of their lung function. I commonly see people whose self-reported symptoms are minimal but whose lung function is poor. This makes a big difference in what medications to use. Second, listening to the lungs with a stethoscope, called auscultation (aw-skull-TAY-shun), cannot tell you all you need to know. Even if the lungs are clear, testing may reveal diminished lung function.
An important part of spirometry that is underutilized is called bronchodilator reversal. What this means is, after measuring the lung function, the patient is given a “breathing treatment” with albuterol and then the lung function is measured again. A significant change in lung function, or lack thereof, is a very important clue as to how active a person’s asthma is.
If you have asthma, and especially if you take regular asthma medications, you need to have your lung function measured to ensure that you are doing all you need to do to keep your asthma under control.
Dr. O
Post-post mini rant: A huge pet peeve of mine is calling spirometry “Pulmonary Function Testing” (PFT). Spirometry is one component of PFT, with the others being measurement of lung volumes and measurement of how well gas moves between the lungs and the bloodstream, called DLCO. Full PFTs are important in the diagnosis and management of many lung diseases, but asthma is not one of them.
November 19th, 2008
In a recent study from Canada, researchers set out to determine how many obese individuals had been misdiagnosed with asthma. What they found was quite interesting. Nearly 30% of all patients in the study, obese or not, had been misdiagnosed. That’s a pretty big number. Can it really be true?
As with most things in medicine, the devil is in the details. Close examination of the study methods reveals some potential biases and limitations that make the true number of asthma misdiagnoses lower. Still, the authors bring to light some important truths about the diagnosis of asthma. First, asthma can be difficult to diagnose. Second, objective measurements of lung function are woefully underutilized and often poorly interpreted. Third, diagnostic challenge testing is also underutilized.
Doctors like to use pithy sayings to guide their practice habits. These are often referred to as clinical pearls. I heard two such sayings often in my training, “If you hear hoof beats, don’t go looking for Zebras.” and “Common things are common.” So when a person comes to me and says, “When I get around my girlfriend’s cat my chest feels tight.”, I’m thinking asthma. The history is often not so straightforward, however. That’s why lung function measurements, spirometry, are so important. If a person is very symptomatic and his spirometry is normal, that makes the diagnosis of asthma less likely. Conversely, if the spirometry looks like asthma and changes a certain amount following treatment with albuterol, that can be diagnostic for asthma. If I see enough red flags in the history and work-up, I’ll often perform a methacholine challenge test. This test gives subjects gradually increasing doses of inhaled methacholine, a chemical which makes asthmatic’s lungs constrict slightly. After each dose, spirometry is performed. If the lung function falls a certain amount, that indicates asthma. The test can take up to a couple of hours.
Back to the study. As I said, the take home message is right on, but I doubt the numbers are very accurate. First, asthma was defined as, “Has a physician ever told you you have asthma.” This is a pretty loose definition. Second, the average time since diagnosis was 15 years. This means that if you are 21 and a doctor told you at age 6 that you have asthma, you could be in the study. Third, only 20% of the misdiagnosed group vs. 45% of the confirmed group were taking daily asthma meds. This tells us that the misdiagnosed group had milder symptoms and likely a less certain clinical diagnosis to begin with. Finally, the phone call method of selection may have led to more patients who already doubted their diagnosis to opt for the study.
If you have questions about asthma, your local allergist is an asthma expert who can answer them.
Dr. O
October 10th, 2008
Both Symbicort and Advair contain drugs called long acting beta-agonists, or LABAs for short. Symbicort contains formoterol and Advair contains salmeterol. Advair and Symbicort also contain inhaled corticosteroids(ICS), fluticasone and budesonide, respectively. This combination of medications has been repeatedly shown in multiple prospective, randomized placebo-controlled trials to improve symptoms, lung function, and quality of life in asthmatics. More importantly, combination ICS/LABA medications have been shown to reduce asthma exacerbations. So what’s the problem?
The problem is, there are now two large meta-analyses which have shown an increased risk of adverse events in patients receiving LABAs. A meta-analysis pools data from multiple trials in order to achieve higher statistical power. These meta analyses have serious limitations, however.
The first meta analysis was published by Dr. Shelley Salpeter, a primary care physician, in June, 2006. It examined the use of salmeterol. Among the co-authors were her father, an astrophysicist, and her son, then a high-school student. Remarkably, and somewhat disconcertingly, the study was published in the Annals of Internal Medicine, one of the most rigorous and respected journals in the field. It set off a firestorm of controversy in the asthma community and was roundly panned. The primary flaw in the Salpeter paper was the large number of patients who came from the inaptly named SMART trial, where subjects were not required to utilize ICS along with their salmeterol. That is a big no-no. Not surprisingly, the majority of serious adverse events in the meta-analysis came from the SMART trial. A follow-up meta-analysis published by respected asthma physicians Hal Nelson and Jean Bousquet, among others, confirmed what previous trials had shown- patients receiving combination ICS/LABA medications have fewer exacerbations and no increased risk for serious adverse events.
Now, a new meta-analysis has come out examining formoterol. Apparently, the authors have not boned up on their recent history, because they repeat the same fatal flaw of the Salpeter paper- they included subjects who were not required to utilize ICS concomitantly with their LABA. Predictably, the results are similar. The shock value headline will read, “57% increase in serious non-fatal events!”, but the reality is that for every 1000 asthma patients in the analysis, 16 formoterol patients had a serious event and 10 placebo patients had a serious event, so the absolute risk increase is only 0.6%. Additionally, the meta-analysis does not tell us whether those 6 extra patients were on formoterol alone or in combination or what dose of formoterol was used.
The take home message is this: if your asthma is bad enough to require combination ICS/LABA therapy, then you can be reassured that there a wealth of data and experience supporting their effectiveness and safety.
Disclaimer: I have no financial ties to either GlaxoSmithKline(Advair) or AstraZeneca(Symbicort), or to any other pharmaceutical company for that matter. On occasion, I eat a grilled chicken salad at lunch with a GSK rep.
