Crowd-sourced symptom data in pollen allergy: testing a novel study approach for assessing the efficacy of food supplements

Pollen allergy can have a significant impact on a person’s quality of life. Recently, food supplements have gained in importance for persons suffering from pollen allergy. Still, there is not much research data on the efficacy of food supplements and the experienced relief, especially when choosing study designs that require less effort than randomized controlled trials (RCT).

A food supplement containing an Astragalus membranaceus root extract was administered to 328 voluntary participants during the 2018 birch, grass and ragweed pollen season in Austria. Participants documented their symptoms and medication intake in the online Patients Hay-fever Diary (PHD). All participants were asked to answer a quality-of-life questionnaire at the end of the study. Alongside with the adherence rate the overall symptom load index (SLI) and the nasal symptoms of the participants were monitored and compared to a filtered group of users from the PHD.

The adherence rates range from 32.8% to 77.3%. Additional data like a quality-of-life questionnaire and the mean overall/nasal SLI showed differences between participants and the baseline. However, they were only statistically significant for the ragweed pollen season and the nasal symptoms.

The study design relied on the evaluation of crowd-source symptom data alone by comparing the participants with a baseline. The participant adherence turned out lower than expected; however a trend for reduced symptoms was found and is also supported by the quality-of-life questionnaire.