A Review of Interoperable Electronic Health Record Systems: Standardisation, Patient Identity, Consent, and Privacy

Patient records remain fragmented across providers,and recent reviews still report interoperability, privacy, and data quality problems as open. This paper reviews eleven peer reviewed studies published from January 2025 onward whose authors, titles, venues, and DOIs were individually verified. They cover EHR interoperability and HL7 FHIR, AI-assisted standardisation, consent, patient identity linkage, privacypreserving sharing, and machine-learning medication-safety support. The comparison yields seven research gaps: standards fragmentation, unvalidated AI-assisted standardization,unenforceable or unverifiable consent, an identity-linkage and re identification trade-off, scarce real-world validation, limits of intelligent support, and thin implementation evidence for resource-constrained multi-hospital settings. UniCare Phase 1,built with React.js, Django REST APIs, and MySQL, is then positioned against these gaps. It provides governed hospital onboarding, a Universal Patient ID, visit-wise records, and authorisation-based sharing. It does not implement standards based FHIR exchange, AI components, or evaluated record matching, and the paper says so explicitly. UniCare’s intended research value is cross-provider intelligent support enabled by a unified record rather than a new identifier scheme; that layer is planned and is not claimed here.