BACKGROUND: The sharing of health data (HD) remains intensely debated, such as in the context of the European Health Data Space. While HD sharing has great potential, the factors influencing patients' willingness to share their HD remain unclear. Understanding patients' perspectives is crucial to enhancing their motivation to share their HD, both with healthcare providers (primary use [PU]) and for purposes unrelated to patient care (secondary use [SU]).

OBJECTIVE: This overview of systematic reviews (SRs) synthesizes and qualitatively appraises available research on factors affecting patients' willingness to share their digital HD for PU and SU.

METHODS: The MEDLINE, Embase, and Scopus literature databases were searched in June 2023, complemented by additional searches, to identify SRs focusing on the determinants of patients' willingness to share HD published from 2013 to 2023. SRs underwent a multistage screening process using the inclusion and exclusion criteria based on the Population, Concept/Construct, and Context (PCC) framework, followed by data extraction and quality assessment using revised measurement tool to assess systematic reviews (R-AMSTAR2). Factors were categorized through a combined deductive-inductive thematic coding process, considering theories on HD sharing and technology acceptance.

RESULTS: Eleven SRs published between 2014 and 2021 were included, encompassing 321 articles with diverse study designs. Forty-one influencing factors (labeled as facilitators, barriers and inconsistent for unclassifiable factors) were identified and grouped into 15 main categories: 22 facilitators, nine barriers, and four inconsistent factors for PU and 13 facilitators, six barriers, and six inconsistent factors for SU. The key facilitators for PU and SU included higher education, trust, confidentiality, and transparency. The major barriers for PU and SU were privacy and security concerns. The R-AMSTAR2 overall confidence rating of all SRs was critically low.

CONCLUSION: Our findings highlight modifiable and nonmodifiable factors affecting patients' willingness to share their HD. Policymakers and healthcare providers should focus on modifiable factors such as individual usefulness, public benefit, and privacy and security concerns. High-quality SRs are urgently needed to provide reliable recommendations and to develop a holistic, practical framework.

PROTOCOL REGISTRATION NUMBER: CRD42023429302.