OBJECTIVES: Daily questionnaires are commonly used Patient-Reported Outcomes (PROs) to collect data on disease symptoms and quality of life on a daily basis in support of clinical trial endpoints. These clinical trials sometimes can last significantly longer than a year and the patients’ compliance and response time to the same daily questionnaire may vary significantly over time. Our aim is to understand how patients’ behaviour changes throughout a longer study with respect to daily PROs.

METHODS: We used data collected from 1463 patients randomized in three respiratory clinical trials investigating benralizumab in patients with nasal polyps (NCT03401229) or tezepelumab in patients with asthma (NCT03347279 and NCT03406078). The daily questionnaires were completed by patients using electronic handheld PRO devices at home which collected the times of when they started and completed the questionnaires. We used logistic regression to identify unbiased coefficients associated with compliance and general linear model with log-logistic distribution to fit the response time using patient, site and calendar (e.g. time and date of completion) features as covariates.

RESULTS: Compliance decreases linearly in time after randomization, but the rate of decrease is higher in younger patients. Adherence throughout the study is correlated with the 14-day pre-randomization compliance and increases in the vicinity of a scheduled visit. Patients are also more compliant with assessments occurring in the morning and during working days compared to evening ones and non-working days respectively. Older patients (>69 years old) can take up to three times longer to complete the PRO but the response time significantly decreases during the first month of the study for all patients. Morning assessments and presence of adverse events increase the response time.

CONCLUSIONS: Detailed PRO analysis on compliance and response time of daily questionnaires in clinical trials provide significant insights on how to optimize longitudinal clinical studies in a patient-friendly manner.