Introduction
The prevalence of allergies is increasing, and the most common manifestation of this are the respiratory allergic diseases such as allergic rhinitis (AR) and asthma1,2. Aomg patients with AR and allergic asthma, allergen-specific immunotherapy (AIT) is the only treatment option that induces clinical and immunologic allergen-specific immune tolerance, thus conferring a long-lasting clinical benefit3,4. Subcutaneous immunotherapy (SCIT), which is the most common form of AIT, has been demonstrated to be highly effective for treating patients with a mite allergy, and/or seasonal pollinosis5. SCIT usually involves administering a gradually increasing dose of the specific allergen to allergic patients until the effective dose is reached, which takes several weeks and is followed by two or more years of maintenance doses6. Patient compliance and education during treatment has been shown to play an important role in guaranteeing the disease-modifying effect of SCIT7. However, the impact of treatment delays on the condition of SCIT patients with allergic diseases has not yet been reported.
At the end of 2019, the global community witnessed the outbreak of the coronavirus disease 2019 (COVID-19) in China, which has subsequently had a tremendous influence on clinical, educational, research, and community responsibilities around the world8. In the event of such a global infectious pandemic, allergy and immunology specialists have suggested that rapid and drastic measures may be needed, which limit or require adjustment of ambulatory allergy services9. Affected by the pandemic, many patients who were receiving SCIT were forced to discontinue or postpone treatment in the hospitals, which led us to consider whether these patients experienced any physical and/or mental impacts because of treatment delay during this period. Real world evidence (RWE) allows for estimates of effectiveness rather than efficacy in various typical practice settings, as well as the examination of clinical outcomes in a diverse study population, which is representative of patients observed in clinical practices5. In this research, we follow up on the physical and mental outcomes on SCIT patients that experienced treatment delays, based on RWE up to one year. This will enable us to develop novel strategies for future SCIT management during the COVID-19 pandemic.
According to the recommendations of World Allergy Organization (WAO) and European Academy of Allergy and Clinical Immunology (EAACI)10,11, a comprehensive set of end-points were chosen for our research. To measure symptom and medication (1) these included visual analogue scale (VAS); daily symptom score (dSS); daily medication score (dMS); and combined symptom and medication scores (CSMS). To measure quality of life (QoL) (2), and psychological burden (3) these included self-rating anxiety scale (SAS); and self-rating depression scale (SDS). These commonly used indices were selected to demonstrate the severity of symptoms, use of medication, quality of life, effect of anxiety and depression related symptoms in patients with delayed SCIT during the COVID-19 outbreak.