Factors affecting participation in web-based Alzheimer's questionnaire surveys: Lessons from the Japanese trial-ready cohort.

Background: Web-based approach is considered helpful for the research focused on screening and early detection of individuals with preclinical Alzheimer's disease (AD); obtaining sufficient responses is critical to the success of such online study.

Objectives: This study examined factors influencing response rates to an online survey about disease-modifying drugs for AD among participants in the Japanese Trial-Ready Cohort (J-TRC) webstudy.

Design: This was a retrospective observational study.

Settings: Online survey in Japan using Google Forms.

Participants: We enrolled the eligible J-TRC webstudy participants who had registered before September 2023. We sent them an invitation e-mail including a questionnaire web address on November-December 2023, in order to conduct an online survey regarding their perceptions of disease-modifying therapy drug that was approved in July 2023, Japan.

Measurements: We analyzed the impact of mailed day of the week (DOW), participant gender, age, employment status, and educational background with/without response to the invitation, quantified by the odds ratio of response.

Results: Among approximately 10,400 J-TRC web study participants who sent invitation emails, the overall response rate was approximately 20 %, without significant influence depending on the DOW when the survey invitation was sent. Individuals who were older (50s-70s), retired, or had higher education levels were significantly more likely to respond, regardless of the DOW. Differences in response rates by sex/gender were observed, but were largely influenced by the employment status.

Conclusions: In order to improve response rates and enhance data quality, these findings provide valuable insights for optimizing the design of future online studies/surveys in the field of AD and dementia, particularly for targeting cognitively unimpaired middle-aged and older populations.