Immunotherapy compliance: comparison of subcutaneous versus sublingual immunotherapy

Patient compliance is critical for successful allergen immunotherapy (AIT). Previous studies suggest that AIT compliance is worse outside of controlled clinical trials, with reported subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) noncompliance at 11% to 50% and 3% to 25%, respectively.

A retrospective review of 384 AIT patients at a single, tertiary care otolaryngic allergy practice evaluated SCIT and SLIT compliance, based on treatment stage. SCIT compliance was defined as the number of 2-week breaks per year or in compliance with their defined schedule: excellent = 2 or fewer; good = 3 to 4; fair = 5 to 6; and poor = 7 or more. Compliance with SLIT was defined as the number of days vials were refilled within the defined expiration date: excellent = 10 days or fewer; good = 11 to 15 days, fair = 16 to 20 days; and poor = 25 or more days. Fisher exact and chi square tests were used for statistical analysis.

Seventy-four SCIT and 200 SLIT patients had data appropriate for analysis. Compliance rates were excellent (62%) or good (22%) in 62 SCIT patients and excellent (31%) or good (35%) in 131 SLIT patients. Comparing excellent compliance rates, SCIT patients had a higher rate of excellent compliance at all stages of treatment compared to SLIT patients (p < 0.05). For SCIT patients there was no significant difference in excellent compliance rates between escalation, first year of maintenance, and greater than 1 year of maintenance (p > 0.05).

The results of this study showed higher rates of patient adherence to treatment protocols among SCIT patients. There was no decrease in SCIT compliance rates across treatment stages.