Allergy immunotherapy may help prevent asthma

By Lorraine L. Janeczko

Allergy immunotherapy (AIT) may help prevent allergic rhinitis (AR) from developing into asthma, new research from Germany suggests.

"These findings have important implications for patient care: first, that AIT works in routine patient care; second, that the choice of AIT treatment plays an important role; and third, that, to benefit most from AIT treatment, patients should be treated for at least three years," principal investigator Dr. Jochen Schmitt, allergist and director of the Center for Evidence-based Healthcare, in Dresden, told Reuters Health by email.

Because reducing the risk for asthma can decrease health care costs significantly, AIT should be initiated early in the allergic disease and be continued for at least three years, the authors recommend.

"Our study is the first to show that AIT can effectively prevent asthma onset in patients with AR. Overall, when we controlled for potential confounders such as age, sex, healthcare utilization due to AR, and use of antihistamines, AR patients who received AIT had an approximately 40% decreased risk of developing asthma compared with AR patients who did not receive AIT," Dr. Schmitt said.

Dr. Schmitt and colleagues used routine health care data from German National Health Insurance beneficiaries to identify 118,754 patients with AR but without asthma who had not received AIT in 2005.

As reported online September 11 in the Journal of Allergy and Clinical Immunology, in 2006, 2,431 patients (2.0%) began AIT.

Between 2007 and 2012, asthma was newly diagnosed in 1,646 (1.4%) patients. Compared with patients receiving no AIT in 2006, the risk of incident asthma was significantly lower in those who were exposed to AIT (risk ratio 0.60).

Sensitivity analyses showed significant preventive effects of subcutaneous immunotherapy (RR, 0.54) and of AIT including native (nonallergoid) allergen preparations (RR, 0.22). AIT taken for three years or longer tended to have stronger preventive effects than AIT taken for a shorter period.

"AIT preventive effectiveness differed between the various products and was highest for subcutaneous immunotherapy and immunotherapy containing native allergens," Dr. Schmitt said.

"Prior to our study there was only limited evidence for the effectiveness of AIT to prevent asthma in patients with AR, from small, methodologically limited clinical trials. Trial evidence cannot simply be generalized to routine care because real life is much more complex than a clinical study," he added.

Limitations to the study include the administrative dataset's lack of information on allergen sensitization, which limited the interpretation of the findings.

Among the study's strengths, the authors note, are its inclusion of all patients with AR who used medical care, and the adjustment for confounders including age, sex, and health care use.

Dr. Sarah K. Wise, MD, who studies otolaryngic allergy at Emory University School of Medicine in Atlanta, told Reuters Health by email, "While clinicians treating allergy have suspected, based on prior smaller unblinded trials, that allergy immunotherapy confers benefit with regard to asthma prevention, this study examines real-world allergy treatment."

"Routine clinical medicine differs from controlled clinical studies with regard to patient oversight, monitoring, and compliance. It is important for clinicians to know that AIT may prevent asthma development in the real-world treatment setting, outside of controlled studies," she said.

"In general," advised Dr. Wise, who was not involved in the study, "the decision to proceed with allergy immunotherapy must always be undertaken with full consideration of the patient's overall health status and treatment goals. Although generally considered safe, allergy immunotherapy has known potential risk of serious systemic reactions and anaphylaxis, so patients must be informed of these risks."

SOURCE: http://bit.ly/1Msu3Fu

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