Identifying Causes of Subcutaneous Immunotherapy Non-Adherence in Patients with Allergic Rhinitis: A Cross-Sectional Study.

Abstract

Purpose: To investigate the reasons for discontinuation of subcutaneous immunotherapy (SCIT) in patients with allergic rhinitis (AR) and to inform strategies for improving treatment adherence.

Materials and methods: In this single-center retrospective cross-sectional study, 794 AR patients (age 1-60 years) who initiated standardized SCIT with house dust mite extracts at Shenzhen University General Hospital between December 2019 and July 2023 were included. SCIT followed a structured dose-escalation and maintenance protocol: weeks 1-4, 0.1-0.8 mL (50 TU/mL); weeks 5-8, 0.1-0.8 mL (500 TU/mL); weeks 9-14, 0.1-1.0 mL (5000 TU/mL); weeks 14-152, monthly 1.0 mL (5000 TU/mL). Symptom severity was assessed using a visual analogue scale (VAS) at baseline and at 6 months, 1, 2, and 3 years; <20% VAS reduction and/or patient-reported insufficient improvement after ≥12 months defined "unsatisfactory efficacy". Structured telephone follow-up was used, with caregivers interviewed for pediatric patients. All patients provided detailed contact information; no loss to follow-up occurred.

Results: Fifty-eight patients (7.30%) discontinued SCIT (27 males, 31 females; mean age 14.71 ± 10.76 years). Leading reasons were relocation for education, work, or travel (53.45%), perceived lack of efficacy (17.24%), limited time (8.62%), and pregnancy/gynecological conditions (6.90%). Females were more likely to discontinue due to relocation, males due to unsatisfactory efficacy; age and comorbidities were not significantly associated with dropout.

Conclusion: SCIT discontinuation was mainly driven by relocation, treatment expectations, and logistical factors, with gender-specific patterns. Tailored pre-treatment counseling, assessment of lifestyle and reproductive plans, and strategies to maintain continuity of care may reduce dropout and improve long-term adherence.