Critically Appraised Topic

Immunotherapy for Asthma

Mike Douvas

9/12/97

Clinical Scenario:
58 YO non-smoking AAF with recent onset 2 years ago of difficult to control asthma on albuterol
and fluticasone inhalers with need for frequent hospitalizations for flares and subsequent bursts of
oral steroids. Skin testing is positive for multiple allergens.

Clinical Question:
Is there a role for immunotherapy (allergy shots) in the treatment of patients with asthma?

Articles:

"A Controlled Trial of Immunotherapy for Asthma in Allergic Children," N. Franklin Adkinson, Jr. et al in The New England Journal of Medicine, 1/30/97, Volume 336, Number 5, pp.324-331.

"Ragweed Immunotherapy in Adult Asthma," Peter S. Creticos et al in The New England Journal of Medicine, 2/22/96, Volume 334, Number 8, pp.501-506.

Critical Review of Study (Adkinson et al.):

I. Are the results valid?

1. The assignment of patients to treatments was randomized. 121 children with moderate to severe perennial asthma were randomly assigned to receive immunotherapy or placebo and were followed for 18 months.

2. Follow-up was complete with eight children in the immunotherapy group and three in the placebo group dropping out because of "move, family problems, or noncompliance."

3. Patients were analyzed in the groups to which they were randomized.

4. Patients, health workers, and study personnel were "blind" to treatment, but reactions to immunotherapy may have posed a problem. 70% of treatment group and 95% of placebo group received the target maintenance dose for at least 18 months. Further, 34% of treatment group and 7% of placebo group had systemic reactions to injections. Both may have tipped off study participants as to results of randomization.

5. The two groups were similar at the start of the trial (see tables 1 and 2).Patients were from diverse socioeconomic and racial backgrounds.The study was designed to include children with strong allergic history(high IgE, positive skin tests, personal & family histories of atopy). The only exclusion was for families unwilling to give up furred pets.

6. Aside from the experimental intervention, the groups were treated equally.

II. What are the results?

1. Several outcome measures were analyzed with the principal one being daily medication score. Other outcomes evaluated were bronchial sensitivity to methacholine, use of medical care, symptom scores, and peak flow rates.

2. There were no statistically significant effects of immunotherapy. Both groups did well in terms of improved symptoms and less use of medications. The percent of patients achieving partial or complete remissions was higher in the treatment group at two years. Also, medication scores went down by more, use of inhaled and oral steroids were lower,and peak flow changes were higher in the treatment group but all results were not statistically significant. Symptom scores went down by more in placebo group (again,however, not statistically significant). Outcome measures were very precise.

III. Will the results help me in caring for my patients?

The results can probably be applied to both my pediatric and adult patients. Immunotherapy is probably not indicated for asthma. Both groups did well without statistically significant differences between them. Immunotherapy is a large commitment and not without risks(ie, systemic reactions). One could argue about the size of the study and its possible lack of power. Patients were well managed medically prior to enrollment, which also may make it not applicable when there are compliance issues. A final caveat occurs when there are concurrent rhinoconjunctivitis symptoms as immunotherapy is probably efficacious in relief of these symptoms.