House dust mite allergen immunotherapy for monosensitized versus polysensitized patients with allergic rhinitis: A systematic review and meta-analysis

BACKGROUND: Most patients with allergic rhinitis are polysensitized. The efficacy of house dust mite (HDM) allergen immunotherapy (AIT) compared between monosensitized and polysensitized patients remains limited. OBJECTIVE: To systematically review the efficacy and safety of HDM AIT compared between monosensitized and polysensitized patients with allergic rhinitis. METHODS: We searched PubMed/MEDLINE, Scopus, EMBASE, and the Cochrane central register of Controlled Trials (CENTRAL) until June 2022. The primary outcome was the changes from baseline in total nasal symptom score (TNSS). Secondary outcomes were changes from baseline in total medication score (TMS), combined symptom medication score (CSMS), visual analog scale (VAS), Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) score, immunological parameters, and adverse events (AEs). RESULTS: Of 13 eligible studies, 10 prospective cohorts, 2 retrospective cohorts, and 1 matched cohort, we identified 10 studies for quantitative synthesis. There were 1,113 patients with allergic rhinitis, 566 with HDM monosensitization and 547 with polysensitization to HDM and other allergens. There was no significant difference in the pooled mean changes of the 2 groups in TNSS (SMD -0.05, 95%CI: -0.22 to 0.11, p = 0.532) and VAS (SMD -0.20, 95%CI: -0.42 to 0.01, p = 0.060) with moderate certainty of evidence. The changes in TMS, CSMS, and RQLQ were similar between the 2 groups with very low certainty of evidence. The AEs were mild and comparable between the 2 groups. The immunological indices remained inconsistent and were not predictive of clinical responses. CONCLUSIONS: A single HDM AIT similarly improved clinical outcomes in monosensitized and polysensitized patients with allergic rhinitis.