Linking Healthcare Data

The 'Evidence Synthesis' project will establish the accuracy and validity with which routinely collected healthcare data can be linked and used to provide a routine method for assessing the safety and effectiveness of medicines in children.

Our aim is

  • to create a linked national dataset for pharmacovigilance in children and
  • establish the completeness and accuracy of the linked data by comparing ‘virtual child cohorts’ (derived from the linked data) with established disease registries, where the data is acquired prospectively by direct patient contact and follow up


The initial questions we will address are:

  • What information is collected routinely in the NHS that can be used for pharmacovigilance?
  • What is the best method of linking datasets to support pharmacovigilance and pharmacoepidemiology?
  • What are the limitations of the data?
  • How accurate are routinely acquired NHS data in Scotland?
  • What are the technical barriers to linking routinely acquired health data?

A range of of primary and secondary data will be linked by either deterministic matching, using the unique patient identifier – the Community Health Index (CHI) - or by probabilistic matching, where CHI is not available.

ISD Linkage fig

The linked data will be used to establish ‘virtual’ disease registries and cohorts for children.

The validity of the ‘virtual child cohorts’ derived from linked NHS data will be assessed by direct comparison against information held in prospectively acquired patient registries, such as the Scottish Children’s Asthma Registry (SCAR), The SEATON Birth Cohort and The Scottish Study Group for the Care of Diabetes in the Young (SSGCDY) dataset.

Once the linked databases have been validated data mining can be used for pharmacovigilance studies.


This project will establish the extent to which linked NHS data can be used to assemble ‘virtual’ disease registries and population cohorts to provide a routine method for the post-marketing surveillance of medicines in children. We will identify the strengths and weaknesses of linked data and describe where improvements can be made in terms of data quality and linkage strategies. This will contribute to the growing expertise and excellence in health informatics research in Scotland and provide NHS Scotland with a research tool to maximise outputs from the high quality data held at ISD, facilitating the research to ensure effective treatment, and improved patient safety and health outcomes for children in Scotland.

If you would like more information please contact Brad Kirby (