Bridging the 'Ten Walls' of Japanese Healthcare Data: A Semantic Mapping of JIPAD to HL7 FHIR R4 and Gap Analysis

Details

Japan faces significant challenges in medical data interoperability, often referred to as the 'Ten Walls.' This study aimed to develop a formal mapping of all 122 variables from JIPAD (Japanese Intensive Care Patient Database) to HL7 FHIR R4. The evaluation used ISO 21564-based semantic equivalence scoring across three tiers: High, Partial, and Low/No Equivalence. Of the 114 resulting mapping entries, 97 (85.1%) achieved High Equivalence using LOINC/SNOMED CT, while an additional 12 (10.5%) achieved Partial Equivalence via JP-Core extensions or FHIR R4 Core mechanisms. This yielded a combined technical feasibility of 95.6%. Crucially, the only entries classified as Low/No Equivalence were attributable to Japan's proprietary disease classification system embedded in the DPC reimbursement framework, rather than technical deficiencies. Furthermore, JIPAD's pseudonymization architecture demonstrated a high capability for record linkage (99% DPC data matching). The authors conclude that JIPAD is technically and architecturally ready for FHIR integration at 95.6%. The remaining 4.4% barrier is identified as purely institutional, stemming from MHLW policy frameworks governing the DPC system, making JIPAD integration essential for a clinically meaningful Japanese Health Data Space (JHDS) by 2027.