Safety and treatment compliance of subcutaneous immunotherapy: A 30-year retrospective study.

Abstract

BACKGROUND\nSafety and treatment compliance are still considered important shortcomings of subcutaneous immunotherapy (SCIT).\n\n\nOBJECTIVE\nTo assess the rate of side effects (SE) to SCIT and treatment compliance at a hospital medically supervised facility.\n\n\nMETHODS\nA retrospective review of patients with allergic rhino-conjunctivitis (ARC) with or without asthma, who received SCIT to mites and pollens from 1988 to 2018, was performed. The information was collected from patient s allergen immunotherapy forms that had been prospectically filled in by expert physicians.\n\n\nRESULTS\nTwo thousand two hundred patients (50.2% males; mean age 29.4\u202f±\u202f11.7 years) received 3037 SCIT courses. A total of 91,187 injections were given, with a mean SCIT duration of 2.5\u202f±\u202f1.9 years. Nine hundred fifty-seven patients (43.5%) were compliant as they completed the minimally required treatment duration of 3 years. A total of 1087 SE (1.2% of all injections; 76.8% local reactions) were reported in 513 patients (23.3%). There were 42 anaphylactic reactions (in 29 patients) during the study period; two of these were severe. Adrenalin was administered only once. No anaphylactic shock was reported. Only 39 patients (1.8%) discontinued SCIT because of SE, the majority of whom (24; 61.5%) because of systemic reactions (urticaria, asthma, anaphylaxis). Parietaria vaccines were the most frequently associated to SE. Female gender, number of vaccines administered (2 vaccine vs. 1 vaccine) and year of SCIT inception (1996-2018 vs. 1988-1995) were independently associated to SE.\n\n\nCONCLUSION\nSCIT, although not absolutely free of risk, is safe and well tolerated. There is still room for improvement of treatment compliance.