Quality of evidence assessment of direct and indirect digital biomarkers

Abstract

Wearable, portable, implanted, or ingestible digital devices are used to gather objective, quantifiable, physiological, and behavioral parameters known as digital biomarkers. Meta-analyses of digital biomarkers have increased in recent years, causing the need for evaluating evidence quality. This study evaluated the quality of direct and indirect digital biomarker evidence. Using the definition of digital biomarkers, a search of PubMed and the Cochrane Library was undertaken for articles published in 2019 and 2020. English meta-analyses comparing the clinical effects of therapies using digital biomarkers to those using non-digital biomarker-based interventions were considered. The GRADE technique was used to evaluate the quality of the evidence synthesis in the meta-analyses. The final analysis comprised 26 articles with 95 reported outcomes (26/95, 27.4% direct and 69/95, 72.6% indirect digital biomarkers). There was moderate quality evidence for most indirect digital biomarkers (64/69, 92.8%) and the quality of evidence was low for five outcomes (7.2%). Direct digital biomarkers generated 23.1% (6/26) high-quality evidence and 76.9% (20/26) moderate-quality evidence. Most direct and indirect digital biomarkers provided moderate quality evidence, however, direct biomarkers, because they influence physiological indicators, generate higher evidence.