Both Subcutaneous & Sublingual Immunotherapies Effective in Treatment of Allergic Rhinitis
Allergic rhinitis (AR) is a global health problem and one of the most common conditions seen by otolaryngologists. It affects between 10% and 30 % of the population worldwide. It is commonly managed by pharmacotherapy. In a recent study, researchers have found that both subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) are effective in adults with allergic rhinitis or rhinoconjunctivitis (AR/C). The research has been published in The Laryngoscope on April 30, 2021.
For patients with refractory symptoms who failed to respond significantly to pharmacotherapy, allergen immunotherapy (AIT) has emerged as an alternative treatment option. AIT may be administered as SCIT or SLIT, both of which have demonstrated efficacy in randomized controlled trials (RCTs). However, only a few trials have compared the two. Therefore, researchers of the University of North Carolina School of Medicine, USA, conducted a study to determine whether subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT) better improves patient outcomes and quality of life for adults with allergic rhinitis or rhinoconjunctivitis (AR/C) with or without mild to moderate asthma.
Researchers conducted a systematic review methodology that was based on the Cochrane Collaboration handbook and Preferred Reporting Items for Systematic Reviews and Meta‐analyses. They searched four databases (PubMed, Cochrane Library, EMBASE, and Web of Science) and included a total of 53 RCTs. The major outcomes assessed were symptom score (SS), medication score (MS), combined symptom medication score (CSMS), and Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ).
Key findings of the study were:
- Upon evaluating 7 SCIT versus SLIT RCTs, the researchers found no significant differences for any outcomes. However, they couldn't conduct a direct meta-analysis due to insufficient data.
- Upon adjusted indirect comparison, they included a total of 46 RCTs over 39 studies for SCIT versus placebo (n = 13) and SLIT versus placebo (n = 33).
- Using indirect meta-analysis, the researchers found statistically significant results favoring SCIT for SS (standardized mean difference [SMD] = 0.40), MS (SMD = 0.26), CSMS (SMD = 0.42), and RQLQ (MD = 0.24).
- They also found statistically significant results favoring SLIT for SS (SMD = 0.42), MS (SMD = 0.40), CSMS (SMD = 0.37), and RQLQ (MD = 0.32).
- On comparing both SCIT and SLIT they found no significant differences for SS (SMD = −0.02), MS (SMD = −0.14), CSMS (SMD = 0.05), or RQLQ (MD = −0.08).
The authors concluded, "SCIT and SLIT are comparably effective treatments for adults with AR/C. More RCTs analyzing SCIT versus SLIT are needed to directly compare the two. "
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