What is the difference between ICD 9 and ICD 10 data?

UK Biobank (UKB) receives linked health-related outcomes data from the Cancer Registry, NHS Digital (Hospital Episode Statistics), Death Registry and Primary Care (GP) providers. Some of the hospital diagnosis data is coded using ICD 10 codes, but some older data is coded using ICD 9 codes.

UKB does not receive Snomed detailed ICD 10 - CM codes. These codes are used in the USA but not in the UK. Other linked health data is coded using Read V2 or CTV3, OPCS3, OPCS4, DM+D, or BNF. Data self-reported by participants is coded using custom UKB codings. These are specified in the Showcase page for each field.

For more detail on the codings and linkages, see Showcase Resources:

596 - Health Outcomes Overview

591 - Primary Care Linked Data

592 - Clinical coding classification systems and maps

593 - First occurrence of health outcomes defined by 3-character ICD10 code

126048 - International Classification of Diseases for Oncology, 3rd edition (ICD-O)

115558 - Linkage from National Cancer Registries

115559 - Linkage from National Death Registries

2112 - Matching Algorithms for External Data Providers

141140 - HES Data Dictionary

138483 - Hospital Episode Statistics

146641 - Mapping inpatient hospital data across England, Scotland and Wales