# NHS Wales hospital datasets
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>Last modified: 23 Jun 2025
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## Introduction

The NHS Wales hospital datasets comprise the **Outpatients Database for Wales (OPDW)**, **Patient Episode Dataset for Wales (PEDW)**,  **Critical Care Dataset (CCDS)**, **Emergency Department Dataset (EDDS)** and the **Intensive Care National Audit and Research Centre (ICNC)**. The hospital datasets **do not include** all mental health or maternity-specific hospital activity.

**OPCS**, **ICD-10**, **NHS National** and **NHS Wales National codes** are used in the OPDW and PEDW datasets. See the [**Coded variables guide**](../coding/coding_intro.md) for further details.

## Coverage of hospital datasets

The hospital datasets cover **inpatient admissions, outpatient appointments**, **critical care**, **Intensive care** and **accident & emergency attendances** at **hospitals in Wales**.

The hospital datasets **include** private patients treated in NHSW hospitals and care delivered by English Trusts.  
The hospital datasets were linked either by NHS number or a combination of alternative patient identifiable fields; **all five hospital datasets will be available in the UK LLC TRE**.
  
**Table 1** Names, temporal coverage and availability of hospital datasets in the UK LLC TRE (the datasets in italics are retired)
| **Name in TRE**|**Full name**|**Domain**|**From**|**Until**|**Data available in TRE<sup>1</sup>** |
|---|:---:|:---:|:---:|:---:|:---:|
|**OPDW**|Outpatients Database for Wales|Outpatients|01/04/2004|Ongoing|TBC|
|**PEDW**|Patient Episode Dataset for Wales|Inpatients|01/04/1995|Ongoing |TBC|
|**CCDS**|Critical Care Dataset|Critical care|01/01/2007|Ongoing|TBC|
|**EDDS**|Emergency Department Dataset|A & E patients| 01/04/2009|Ongoing|TBC|
|**ICNC**|Intensive Care National Audit and Research Centre|Intensive care|01/05/2008|Ongoing|TBC|

<sup>1</sup>As documented in the data sharing agreement.
  
For further details see the [**NHS Wales Hospital Activity**](https://statswales.gov.wales/Catalogue/Health-and-Social-Care/NHS-Hospital-Activity/Outpatient-Activity) and [**NHS Wales Data Quality Standards**](https://dhcw.nhs.wales/information-services/information-standards/data-quality/data-quality-standards/) webpages.

## Background

<details>
  <summary>Production of hospital datasets for research purposes</summary>