[Persistence and frequency of prescriptions of subcutaneous allergen-specific immunotherapy (SCIT) prescribed within the German statutory health insurance].

Background and Purpose: In accordance with guidelines subcutaneous allergen-specific immunotherapy (SCIT) should be continued for at least 3 consecutive years, which makes compliance to an issue of special importance. Measuring this compliance poses a methodological challenge. The aim of this study is to analyze persistence (reuptake of SCIT in the following years) and frequency (mean number of prescriptions) with the help of secondary data.
Methods: The sample, which was taken from a regional prescription database, includes all members of the German statutory health insurance, who received at least one prescription of selected allergen extracts between January 1, 2003 and June 30, 2006. In addition to persistence, average prescriptions for each year of therapy were used to compare long-term SCIT and short-term SCIT. Based on mean number of prescriptions per year, it was examined whether persistence is higher in short-term than in long-term SCIT.
Results: Mean number of prescriptions is significantly different in the 1st (2nd; 3rd) year of therapy: 1.50 (1.31; 1.28) prescriptions for long-term SCIT, 1.30 (1.42; 1.42) prescriptions for short-term SCIT, and 1.10 (1.12; 1.14) prescriptions for a shortened therapy regimen with an adjuvant-supported allergoid. As presented, persistence is decreasing. Altogether 45% of SCIT patients continue therapy in the 2nd year. In the 3rd year of therapy, there are only 24% of patients remaining. Persistence rates to a certain degree seem to be dependent on the application form.
Conclusion: The analysis of this secondary dataset has found that nonpersistence may jeopardize the therapy according to guidelines to a greater extent than expected from the literature. Except for one allergen extract the differentiation between long-term and short-term SCIT seems diffuse. Packages for consecutive treatment are used not only in long-term SCIT, but also in short-term SCIT regimens, if they are available. The analysis provides first hints that a shorter therapy regimen supports persistence of SCIT during the 2nd and 3rd year of therapy.