Data collection for site-centric study approaches can guarantee standardised approaches to measurement. Furthermore, certain assessments may be difficult to replace with self-assessments at home and undermine the rigour and reproducibility of results.3 However, site-centric approaches may be more costly in terms of resources, such as staff and patient time and carbon footprint, and a potentially narrower participant pool.

Digitally enabled studies may include outcome assessment and passive long-term follow-up using routinely collected electronic healthcare record (EHR) data. This not only reduces costs associated with data collection, but also minimises lost to follow-up assuming participants have not withdrawn from the study. Health data linkage is a method of gathering information from distinct sources (eg, hospital registries, administrative claims) about the same patient or group to create a more comprehensive set of data.7 The disadvantage is that not all outcomes can be suitably assessed using EHR data and an a priori decision would be needed on how any given outcome is being defined by generating lists of all possible codes related to it.8 9 Furthermore, they may not be standardised as the data is not primarily collected for research purposes.

Digital Health Technologies (DHTs) capturing digital biomarkers ‘objective measures of physiological, pathological, anatomic, behavioural, social or activity characteristics, and patient self-report using digital technology’ are promising new tools for advancing precision medicine and supporting clinical trials.1 3 10 While many digital biomarkers are still being validated, in future, they may provide detailed information on physiological processes and explain, influence and/or predict health-related outcomes.11 12 They may also inform diagnostics, dosing titration and serve as endpoints for clinical trials.1 13

Patient-generated health data, including PROs,14 are an integral part of digitally enabled clinical research. Increased use of internet access, home computing and smartphones, in combination with wearables, and biosensor technology provides the opportunity to remotely collect patient-generated health data that are closer to the real-world daily contexts of patients while still allowing for rigorous control, support and management.15 Such technology enables participants to provide data at a time which best suits them, thus potentially maintaining participant motivation and retention.

PROs capture patient’s perspectives, contributing to a more holistic and comprehensive assessment of the safety, efficacy and tolerability of interventions under investigation.16 PROs have traditionally been measured using paper-based questionnaires completed by participants while at site visits. However, technological advances have facilitated the development of ePROs.17 Advantages of using ePROs include reduction of administrative and respondent burden, reduced data entry errors and real-time data collection, which could allow patients to remain at home. Furthermore, ePROs can be configured to trigger notifications that alert research and clinical teams in case of important clinical symptoms. These alerts can prompt more timely clinical intervention and onward referral to specialist care if required as exemplified in the Therapies for Long Covid study (b ox 1).

Led by researchers from the University of Birmingham the TLC Study aims to identify and recruit non-hospitalised patients with Long COVID with symptoms lasting 12 weeks or more to a major digitally enabled clinical study using CPRD primary care data.6 The TLC study links to a digital platform (Atom5) to facilitate the capture of patient-generated data including self-report symptoms, quality of life and work capability.6 17 A subgroup of patients are providing blood and other biological tests, with a single site visit, to understand the immunology of Long COVID, and will wear a device to remotely measure their heart rate, oxygen saturation, step count and sleep quality.