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  • Writer's pictureProf. Dr. med. Felix Nensa

The relational FHIR data model

Updated: May 22

Introduction to FHIR

Fast Healthcare Interoperability Resources (FHIR, pronounced "fire") is a standard framework created by the Health Level Seven International (HL7) for exchanging healthcare information electronically. Its primary aim is to facilitate better and more efficient communication of healthcare data among different healthcare systems.

Core Features of FHIR

FHIR is designed to be simple and easy to implement, using existing logical and theoretical models to provide a consistent, easy-to-implement, and rigorous mechanism for exchanging data between healthcare applications. It's based on emerging industry approaches, including RESTful APIs and JSON.

The FHIR REST API is a critical component of this standard. It leverages RESTful principles, which are popular in web development, for accessing and modifying healthcare data. REST, or Representational State Transfer, is an architectural style that enables the requesting systems to access and manipulate web resources using stateless operations. This API allows for a range of operations, including reading, updating, deleting, and creating healthcare data in a standardized format.

FHIR's Flexibility with Database Models 

FHIR's flexibility allows it to be used with various database models, including NoSQL databases. NoSQL databases are known for their ability to handle large volumes of unstructured data and their scalability. The linkage of FHIR with NoSQL data models is particularly beneficial in scenarios where healthcare data is vast, diverse, and not strictly structured. This combination supports the rapid development and deployment of healthcare applications that can handle diverse data types, from electronic health records to real-time patient monitoring data.

Challenges of FHIR with NoSQL Databases

However, this flexibility also brings challenges. NoSQL databases do not inherently enforce the kind of structured, relational data modeling that is traditional in healthcare. This can lead to complexities in ensuring data integrity and in representing complex relationships within healthcare data – something that is more straightforward in a traditional relational database environment.

Advantages of the Relational FHIR Model

In a relational FHIR model, the power lies in the inherent structure and flexibility of relational databases. SQL databases excel in representing complex relationships between different data entities, which is crucial in healthcare where interconnections between various elements (like patients, diagnoses, treatments, etc.) are intricate and multi-layered.

Why a relational FHIR model is best for complex analytics, such as needed in business analytics
Relational FHIR Model

The relational model allows for efficient querying and management of these relationships. For example, it's straightforward to model and query many-to-many relationships, such as multiple patients having multiple diagnoses. Additionally, the relational model supports robust transaction management and integrity constraints, ensuring data consistency and accuracy – critical in healthcare applications.

On the other hand, a typical REST-based FHIR API, while highly interoperable and flexible, may not inherently manage complex data relationships as effectively. RESTful APIs often interact with NoSQL databases or employ a resource-based approach, which might not natively support complex queries and transactions like SQL databases. This can lead to challenges in representing intricate healthcare data relationships in a RESTful environment.

Moreover, the performance of a relational database in complex query operations, particularly those involving joins across multiple tables, is typically superior to that of a REST-based approach. This efficiency is critical in healthcare scenarios where timely and accurate data retrieval can have significant implications.

Impact on Business Analytics

Extending the discussion on relational FHIR models, let's explore their impact on business analytics use-cases in healthcare. In a relational FHIR model, the structured format of data is particularly beneficial for business analytics. Here’s why:

  1. Enhanced Data Integration: In healthcare, data comes from various sources - patient records, clinical trials, insurance claims, etc. A relational model, with its standardized schema, simplifies the integration of this disparate data, providing a unified view essential for comprehensive analytics.

  2. Complex Querying Capability: Business analytics often require complex queries, such as longitudinal patient studies or population health trends. Relational databases support these complex queries efficiently, especially when dealing with many-to-many relationships (e.g., patients with multiple conditions treated by multiple healthcare providers).

  3. Data Integrity and Accuracy: Crucial in healthcare analytics, data integrity is well-maintained in relational databases through constraints and transaction controls. This ensures the reliability of analytics outputs.

  4. Real-time Data Analysis: Relational models can support real-time data analysis, essential for operational decision-making in healthcare, such as resource allocation and emergency response planning.

Use-Cases for the Relational FHIR Model

Specific use-cases where a relational FHIR model excels include:

  • Population Health Management: Analyzing trends and patterns in patient data to make informed decisions about healthcare programs and policies.

  • Clinical Decision Support: Providing healthcare professionals with patient-specific insights, derived from analyzing historical data, to aid in clinical decision-making.

  • Resource Optimization: Analyzing patient flow, treatment outcomes, and resource utilization to optimize hospital operations and reduce costs.

  • Patient Care Personalization: Leveraging data on patient history, treatments, and outcomes to tailor individual care plans.

In contrast, typical REST-based FHIR APIs may struggle with these analytics use-cases. While they are great for interoperability and accessing specific data points, typically in the context of a single patient, they may not be as efficient at handling the complex queries and integrations required for in-depth analysis at the organizational level (e.g., ward, department, hospital, etc.).


In conclusion, a relational FHIR model, such as the relational FHIR model by Firemetrics, offers significant advantages for business analytics in healthcare, enhancing data integration, query capabilities, and overall analytical depth and reliability. These capabilities are pivotal in transforming raw healthcare data into actionable insights, ultimately improving patient care and operational efficiency.

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