Query Health: standards-based, cross-platform population health surveillance

Abstract

Objective: Understanding population-level health trends is essential to effectively monitor and improve public health. The Office of the National Coordinator for Health Information Technology (ONC) Query Health initiative is a collaboration to develop a national architecture for distributed, population-level health queries across diverse clinical systems with disparate data models. Here we review Query Health activities, including a standards-based methodology, an open-source reference implementation, and three pilot projects.

Materials and methods: Query Health defined a standards-based approach for distributed population health queries, using an ontology based on the Quality Data Model and Consolidated Clinical Document Architecture, Health Quality Measures Format (HQMF) as the query language, the Query Envelope as the secure transport layer, and the Quality Reporting Document Architecture as the result language.

Results: We implemented this approach using Informatics for Integrating Biology and the Bedside (i2b2) and hQuery for data analytics and PopMedNet for access control, secure query distribution, and response. We deployed the reference implementation at three pilot sites: two public health departments (New York City and Massachusetts) and one pilot designed to support Food and Drug Administration post-market safety surveillance activities. The pilots were successful, although improved cross-platform data normalization is needed.

Discussions: This initiative resulted in a standards-based methodology for population health queries, a reference implementation, and revision of the HQMF standard. It also informed future directions regarding interoperability and data access for ONC's Data Access Framework initiative.

Conclusions: Query Health was a test of the learning health system that supplied a functional methodology and reference implementation for distributed population health queries that has been validated at three sites.

Keywords: Database Management Systems; Healthcare Quality Assessment; Medical Informatics; Public Health Informatics; Systems Integration.

Figure 1

Overall design of Query Health. Various stakeholders can develop queries, which are distributed securely and sent to a variety of data partners. These data partners process the queries and return aggregate counts, so that sensitive data never leave individual sites. Query Health uses a variety of standards: a Query Envelope, a Data Model, Health Quality Measures Format (HQMF), and Quality Reporting Document Architecture (QRDA).

Figure 2

The technologies used in the Query Health reference implementation. Individual pilots varied in their use of these components (see Table 1). Informatics for Integrating Biology and the Bedside (i2b2) is used as a graphical query composer. PopMedNet is the query distribution and authentication engine. i2b2 and hQuery are the back-end data warehouses used by data partners to connect to Query Health. A Health Quality Measures Format (HQMF) is used to communicate queries in a standardized format.

Figure 3

The Informatics for Integrating Biology and the Bedside (i2b2) Query Composer. Queries are composed in the graphical i2b2 query builder using the Query Health Consolidated Clinical Document Architecture (C-CDA) data model. These queries are sent to the PopMedNet (PMN) client adapter, which translates the query into a Health Quality Measures Format (HQMF) and sends it to the PopMedNet portal for distribution.

Figure 4

The Informatics for Integrating Biology and the Bedside (i2b2) Query Processing Engine. At each data partner using i2b2, the PopMedNet Data Mart Client sends a Health Quality Measures Format (HQMF) query to an i2b2 instance with a PopMedNet (PMN) server adapter, which translates the query into i2b2 format for execution. Results are returned in i2b2 XML format to the Data Mart Client by way of the server.