OBJECTIVES:

Longitudinal observational studies play a central role in advancing understanding of the onset and progression of physical and mental health conditions in the real world. However, poor adherence to data capture activities can reduce the generalizability of outcomes and the statistical power to detect effects of interest.

This review aimed to assess participant adherence rates in real-world studies, with a focus on those using digital technologies.

METHODS:

Study publications (published in the last 10 years) were identified through targeted searches of the PubMed database and Google Scholar. Publications were assessed for availability of information on adherence rates and, where appropriate, details of incentives offered.

RESULTS:

Fourteen studies were included in the review. The data show that adherence rates to data capture activities vary significantly. Among studies with daily data collection (n=9), where data collection periods ranged from 7 days to 141 days, adherence to data capture activities ranged from 9% to 96%. Among studies with weekly data collection (n=2), where data collection periods ranged from 4 weeks to 2.5 years, adherence ranged from 63% to 84%. Among studies with less frequent data collection (ranging from every 3 months to yearly, n=3), where data collection periods ranged from 1 to 4.5 years, adherence by the end of the study ranged from 1% to 38%.

Six studies reported offering participants incentives for completion of data capture activities. None of these studies explored whether incentives impacted adherence to data capture activities.

CONCLUSIONS:

Adherence to data capture activities in digital real-world studies is impacted by the duration of the study and the frequency of data capture activities. Future research could investigate the relationship between incentives and adherence for data capture activities across longitudinal real-world studies.