Effectiveness of specific immunotherapy in the treatment of allergic rhinitis: An analysis of randomized, prospective, single- or double-blind, placebo-controlled studies

Background: The effectiveness of specific immunotherapy (SIT) in the treatm ent of allergic rhinitis has been supported by empirical evidence and clini cal experience. Objective: This report is an analysis of multiple studies involving patient s with documented allergic rhinitis. Methods: All studies of the effectiveness of SIT in the treatment of allerg ic rhinitis published in English between the years 1966 and 1996 were ident ified through a MEDLINE(R) search. All prospective, single- or double-blind , placebo-controlled studies were included in the analysis. One author (R.N .R.) extracted data from the studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model for a variety of clinical measures in studies that permitted the extraction of numbers of patients with positive and negative outcomes. Results: Data were extracted from 16 studies of the clinical effectiveness of SIT in the treatment of allergic rhinitis, involving 759 patients (546 a dults, 53 children, 160 all ages). In 15 (94%) of the studies, investigator s concluded that SIT was effective. In the remaining study (the only one co nducted in children), investigators concluded that SIT was not effective. S ymptoms of allergic rhinitis were more likely to improve in patients receiv ing SIT than in the comparison patients (OR 1.81, 95% CT 1.48 to 2.23). Sym ptom-medication scores were significantly lower in patients receiving SIT t han in the comparison patients in all studies using such measures (P < 0.05 ). Conclusion: Results of this analysis support the conclusion that SIT is eff ective in the treatment of allergic rhinitis.