Classifying Asthma

DR. SOPHOCLES: How is asthma classified?
DR. COX: The next slides are from the NHLBI guidelines. The guidelines have a number of tables and I would encourage you to go to the website and download these because these are useful resources and references. In the guidelines, the classification of asthma severity is stratified in three age groups; children 0-4, children 5-11, and then youths and adults 12 and greater. In the classification system there is a slight difference from previous guidelines. The slight difference is called intermittent. In the past it was called mild intermittent. And then in the persistent category we have mild, moderate, and severe.

Now in children 0-4, in terms of classifying persistent asthma, there really has not been a lot of changes. The asthma predictive index that I mentioned earlier is used except that they refer to greater than four wheezing episodes, but with the same major and minor criteria that I mentioned earlier. And in those children, if they meet that criteria, then they’re considered persistent and treatment should be recommended. Once they’re in the persistent category, the severity depends on how often they have symptoms. In this instance, if they have symptoms greater than two times a week they’re considered

mild, if it is daily it is moderate, and if it is throughout the day it is severe. In terms of night time awakenings, one to two times a month is mild, three to four is moderate and more than that is severe. That is the classification system for children zero to four. Again, a subtle change is that intermittent doesn’t have mild in front of it anymore. You are using the asthma predictive index with a slight change in that it is not greater than three, it is greater than four episodes, and one of the major or two of the minor criteria.

The next table is children 5-11 and very similar in terms of the changes. We don’t have the asthma predictive index. What we do have is a little change once they’re in the persistent category. In this case, greater than two times a week for symptoms is mild persistent as it was before, but for night time awakenings, three to four times a month is mild, so less than three would still keep you in the intermittent category and that is a little different from the previous guidelines in which greater than two times a month would put you in the persistent category. These tables now have two domains: impairment and risk. The severity classification will go with whichever of the two is most severe, so if you were mild by the impairment classification and your risk places you into moderate or more severe, your asthma classification would be based on whichever gave you the worst rating.

Then we have the table that is for youths greater than 12 years and adults, very similar to the 5-11 group. In this particular table, they actually include in the impairment the lung function which the others included, but it also gives you an FEV1 over FVC ratio as part of your criteria in judging asthma severity. So, not only are you looking at FEV1 but you are looking at the ratio of FEV1 to FVC because particularly in the pediatric population, it may be more sensitive than the FEV1.

Once you’ve classified a patient’s asthma on your initial evaluation, the remainder of your evaluation is going to be assessing control; so there is actually a different series of tables based on asthma control once you’ve initiated therapy. Some of the suggested questions you should be asking on the patient’s visit are, “Has your asthma awakened you at night or early morning? Have you needed your rescue or quick reliever medication, beta-agonists, more often than usual? Have you needed any urgent medical care for your asthma such as unscheduled visits to your physician, or urgent case clinic or emergency department? Are you participating in your usual and desired activities?” If they say, “No” like “I’m not doing sports,” find out why they are not. Some children may not participate because they can’t and some really don’t want to, and there may be different reasons for that. If they are measuring their peak flow readings, ask them what their recent readings are, or better yet ask them to bring a copy of their record.

Actions to consider on these visits depend on whether the medications are actually being taken as rescribed. We try to ask patients to bring their medications in and we like to re-evaluate their inhaler technique on subsequent office visits. That is now part of the current asthma panel guideline recommendations - to valuate and assess patients’ correct techniques, not only on initial assessment but on follow-up visits. Assess lung function with spirometry and compare it with previous measurements. This would not be at every visit but at appropriate times when you are trying to assess response to treatment if they’ve had increased symptoms. Adjust medication as needed, either step up or down depending on their level of control. The goal of herapy is really to provide control, but with the lowest dose of medications.