Background 

Allergic rhinitis and asthma are important sources of morbidity among adults and children.

Although immunotherapy is sometimes used to treat these conditions, there is little information on its use, adherence, or cost in the general population.

Objective 

We sought to characterize the recipients of immunotherapy for allergic rhinitis and/or asthma with respect to their immunotherapy and utilization of health care services.

Methods 

A combination of automated and manually extracted data was used to identify HMO members with diagnoses of allergic rhinitis or asthma who were treated with immunotherapy.

Costs associated with immunotherapy and related care were examined by linear regression.

Proportional hazards and Kaplan-Meier plots were used to evaluate duration of therapy.

Results 

Of the 122,196 persons with a diagnosis of asthma or rhinitis, 2,667 were also treated with immunotherapy.

Eligibility criteria were satisfied by 603 individuals who had 28,266 encounters for immunotherapy (median 48).

Most patients (>80%) were treated with multiple allergens ; ragweed was the most common single allergen administered.

Thirty-three percent of patients with sufficient observation time completed the intended course of 61 immunotherapy treatments.

Females and younger patients had shorter durations of immunotherapy.

The most common reason for discontinuation of therapy was patient's decision (54%). (...)