Coloured wires plugged into the back of a machine

CRIS Data Linkages


We have set up a Clinical Data Linkage Service (CDLS), which enables us to join or ‘link’ information (‘data’) from Clinical Record Interactive Search (CRIS) with other clinical sources within a secure ‘safe haven’. Safe Havens have been set up in the NHS to ensure that confidential patient information can be linked in a way that guarantees the legal and ethical rights of patients. 

What is Data Linkage?

Data linkage is the joining of two or more independent databases that share a variable at an individual record level – for example, someone’s GP record and their hospital record will share a unique ‘NHS number’. Linkage between different sources helps to improve the quality of information and enables researchers to look at patients’ healthcare in more detail – for example, investigating how general practice and hospital care might be better coordinated. Although datasets may be linked on unique ‘identifiers’ such as NHS number, these are all removed and the information is fully anonymised prior to any researchers being given access to it. 

The CRIS team have co-created an animation with funding from the MRC to explain data linkage and how it has contributed to the evolution of healthcare research, see below:

CRIS Linked Databases

The CDLS has linked CRIS with a number of different databases which are described below: 

Hospital Episode Statistics (HES) are held by NHS Digital (previously the Health and Social Care Information Centre- HSCIC) and include all accident and emergency, hospital admissions and outpatient visits which occur in all hospitals throughout England.

The CDLS has linked CRIS to HES and currently this linkage includes important clinical information such as diagnoses, operations or the speciality of the treating clinician; demographic information such as age, gender and ethnicity; and also administrative data such as methods of admission and discharge. The CDLS holds anonymised HES data on all South London and Maudsley NHS Foundation Trust (SLaM) service users who have attended hospitals anywhere in England. In addition, the CDLS also holds anonymised HES data on the residents of the four London boroughs which form the SLaM catchment area; Southwark, Lambeth, Lewisham and Croydon.

Comparing physical illness and mental health outcomes

This enables researchers to compare physical illnesses and hospital use of SLaM service users to the general population; this linkage also allows researchers to investigate risk factors for physical illness within patient groups or look at how pre-existing physical health problems may impact on the outcomes of mental health treatments.

The linkage between CRIS and HES is important as the information on physical health gained from HES will allow policies and interventions to be developed and evaluated so that the care for people with mental disorders can be improved.

De-identification

In order to link CRIS data with HES, we send identifiable information for SLaM patients (NHS number, name, date of birth, and postcode) to NHS Digital. NHS Digital is able to use this information to link the individual records with hospital records from England. This linkage is legally permissible under the Health Research Authority’s support under Section 251 of the NHS Act 2006. This support enables temporary use of identifiers in a secure environment for accurate linkage. Once NHS Digital has linked the records, all personal information (NHS number, name, date of birth, and postcode) is destroyed and the linked records are supplied back to the CDLS.

These data are fully anonymised prior to any researchers being given access to it.

More information and opting out

Further details about HES can be found on the NHS Digital website.

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

NHS Digital audit

In September 2021, the CDLS was audited by NHS Digital to ensure that the terms and conditions set for this linkage were being abided by and that data were being kept safe and secure.

Based on the audit, NHS Digital identified a number of areas of good practice and concluded that the overall risk of a breach of the terms and conditions with respect to compliance, duty of care, confidentiality or integrity was low. You can read the full audit report here.

The Office for National Statistics (ONS) collects information on cause of death from an individual’s death certificate; this information is held by NHS Digital (previously the Health and Social Care Information Centre- HSCIC). CRIS has been linked with the ONS Mortality data, and the CDLS currently holds date and cause of death information for all patients within SLAM who have died before January 2018. This linkage allows researchers to investigate the relationship between mental health and cause of death.

Understanding lower life expectancy 

Previous research has found that people with mental disorders generally have a lower life expectancy than people without mental disorder, so the linkage between CRIS and ONS Mortality data is important as it helps researchers understand why this may be and provides information that will hopefully help in improving the life expectancy of individuals with mental disorders.

In order to link CRIS data with ONS Mortality data, we send identifiable information for SLaM patients (including NHS number, name, date of birth, and postcode) to NHS Digital. NHS Digital is able to use this information to link the individual records with Mortality records from England and Wales provided by the ONS. This linkage is legally permissible under the Health Research Authority’s support under Section 251 of the NHS Act 2006. This support enables temporary use of identifiers in a secure environment for accurate linkage. Once NHS Digital has linked the records, all personal information, (NHS number, name, date of birth, and postcode) is destroyed and the linked records are supplied back to the CDLS. These data are fully anonymised prior to any researchers being given access to it.

More information and opting out

Further details about the ONS Mortality Data can be found on the NHS Digital website.

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

NHS Digital audit

In September 2021, the CDLS was audited by NHS Digital to ensure that the terms and conditions set for this linkage were being abided by and that data were being kept safe and secure.

Based on the audit, NHS Digital identified a number of areas of good practice and concluded that the overall risk of a breach of the terms and conditions with respect to compliance, duty of care, confidentiality or integrity was low. You can read the full audit report here.

Lambeth DataNet (LDN) is a healthcare database of GP records from practices within the London borough of Lambeth.

The CDLS has linked LDN to CRIS and currently hold anonymised LDN data for patients of the South London and Maudsley NHS Foundation Trust who are registered with a GP in Lambeth. The CDLS also holds anonymised LDN data for residents of Lambeth who are not SLAM patients and this allows researchers to compare how mental disorders affect general health care, comparing people with and without a mental disorder. This data linkage provides a resource for investigating the physical health and health care of people with mental disorders with the aim of improving the care that they receive.

More information and opting out

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

This data linkage provides a resource for investigating the relationship between mental health and educational outcome. The CDLS holds anonymised data from the Department for Education National Pupil Database linked with Child and Adolescent Mental Health Service (CAMHS) CRIS records, as well as an anonymised control sample of all school aged children, who are not patients of the South London & Maudsley NHS Foundation Trust, who were at school and lived in Croydon, Lambeth, Lewisham or Southwark from 2008 to 2013.

This linkage will provide evidence to help families; treating clinicians and health policy makers understand the risk factors for childhood mental illnesses such as autism, attention deficit hyperactivity disorders, psychosis, obsessional compulsive disorders and depression. In addition, it will provide evidence to help clinicians and families understand the impact of childhood mental health on educational outcomes.

This is an important objective for families who seek child and adolescent mental health care is to get their child back on track at school and improve their education performance; this linkage will enable research into how educational risks factors impact childhood mental health treatment and outcome.

More information and opting out

Download the CRIS CAMHS Leaflet for more information.

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

King’s Health Partners (KHP) is an Academic Health Science Centre – a government initiative to bring universities and NHS Trusts together in closer working partnerships. KHP brings together King’s College London with South London and Maudsley NHS Foundation Trust (SLaM), Guy's and St Thomas' NHS Foundation Trust (GSTT), and King’s College Hospital NHS Foundation Trust (KCH). Information sharing is core to KHP – meaning that a doctor treating someone at GSTT is able to see that person’s SLaM or KCH record, or a nurse at SLaM is able to access records at GSTT or KCH.

Reflecting this information sharing by clinical teams, CRIS as an anonymised research database is also bringing together the information contained on different KHP services. 

Effects of COVID-19

Data linkage within KHP is supporting work into the effect of the COVID-19 pandemic on mental health services provided by SLaM.

The COVID-19 pandemic has placed unprecedented strains on all healthcare sectors. SLaM's mental health services have undergone radical changes which may have profound effects on patient care and outcomes, as well as the potential risks that COVID-19 poses to populations already vulnerable to physical disorders. Data linkage between mental health data from SLaM and information on acute hospital attendances from KCH and GSTT has enabled a series of studies which have sought to describe and investigate these issues, responding as rapidly as possible to the needs of the Trust and both local and national priorities.

Renalware 

Renalware is a nephrology database system that was developed at King’s College Hospital (KCH) in 1996. It contains patient records for individuals cared for by the KCH Renal Unit including information on kidney disease, dialysis, and transplants.

The Bridging the Gap Study

Previous research has demonstrated that chronic kidney disease is identified more commonly among patients with mental health difficulties than in the general population, even after controlling for risk factors such as the use of lithium-based medications, socio-economic status and smoking. Furthermore, while dialysis and renal transplantation are life-saving treatments, they are also demanding and impact appreciably on the everyday lives of end-stage kidney disease patients, often negatively affecting their emotional and psychological wellbeing

To address current gaps in our understanding of the link between kidney disease and mental health difficulties, the CDLS are planning to link health records data from the South London and Maudsley NHS Foundation Trust CRIS system with information from Renalware. This linkage will enable the study team to determine the prevalence of mental health difficulties in the kidney disease population and whether there are differences in health outcomes and access to healthcare between kidney patients with and without severe mental health difficulties such as schizophrenia or bipolar disorder.

By undertaking this research, the study team aim to further understanding of kidney disease and mental health difficulties, to provide more effective long-term solutions and inform the management and support provided to kidney patients with severe mental health difficulties.

More information and opting out

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

The embryo, fetus and newborn child are very sensitive to external influences during development, for example the mother's health or lifestyle. External influences during these periods of development can have effects on the long-term physical and mental health of the mother and the child. For example, we know that if a mother has complications in pregnancy, that she herself may suffer from increased risk of ill-heath in later life, such as cardiovascular disease, diabetes or mental health problems.

Understanding health in pregnancy

The aim of the eLIXIR project is to provide information about health in pregnancy and across the life span in a large number of people to help us work out when and how health problems begin, how we might prevent them and what treatments work in some people and not others.

In England, mother, baby and child health records are kept in many different places and are not routinely linked to each other. eLIXIR will pull these data together and anonymise them for use in research. We will link health information from mothers and children, initially starting with local maternity and neonatal data and existing mental health data. Later we plan to link with local primary care data, child clinical health data, national hospital and schools’ data. 

This new and important resource will help us explore the 'life course' of some of the most common diseases and help scientists and doctors to work out how we may prevent them.

Areas where this research register will be used include:

  1. Women’s health: including investigating relationships between pre-pregnancy physical and mental health, common disorders of pregnancy and pregnancy outcomes, and long term consequences of physical and mental health disorders in pregnancy for women;
  2. Paediatrics: including the relationships between maternal physical and mental health disorders in pregnancy and adverse events and exposures in the fetal and neonatal period and their impact on long term physical and mental health outcomes for the child;
  3. Mental Health: including the interrelationships between physical and mental health disorders during pregnancy and pregnancy outcomes, and relationships between maternal and childhood mental health;
  4. Implementation Science and Public Health: including the evaluation of new pathways of care/guideline recommendations to improve maternal and or child physical and/or mental health.

More information and opting out

More information can be found on the eLIXIR website.

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

The Office for National Statistics (ONS) census is a national survey which takes place every 10 years in England and Wales on a nominated day. Every effort is made to include all people resident in England and Wales on that day and ask them questions about their housing, social, health, and living circumstances.

Individuals are also asked about their ethnicity, country of birth, and citizenship. The most recent census was conducted in 2021, and previous census surveys were conducted in 2001 and 2011. The ONS has now linked CRIS to 2011 census data; this linkage is the first between NHS mental health records and census data in England. The data linkage is accessible to approved researchers accessing the dataset within the ONS Trusted Research Environment (TRE).

This data linkage provides a resource for investigating the impact of social and demographic factors, such as employment, migration status, and poverty, on mental health treatment and outcomes. The linkage is being used to examine the social determinants of onset, course and outcomes of severe mental health problems, and is being done through the ESRC-funded Social and Economic Predictors of severe Mental Disorders (SEP-MD) study led by Dr. Jayati Das-Munshi. Results from research using this linkage will be fed back to relevant organisations with the aim of directly impacting patient care and informing changes to NHS policies.

For information about access to the dataset, please contact Dr. Jayati Das-Munshi at jayati.das-munshi@kcl.ac.uk.

More information and opting out

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

A previous data linkage between CRIS and local cancer records (through the Thames Cancer Registry) provided a resource for investigating the relationship between mental health and cancer. The link brought together information on cancer diagnoses, clinical features of the tumour, data from the first three months of intervention, and place and date of death up to 2009.

Cancer and mental health

Through this linkage, a series of analyses were performed to investigate cancer incidence among people with mental disorders, mortality rates after cancer diagnosis, and cancer treatments received in order to inform better treatment strategies.

This initial analysis, found no evidence that cancer presentations are delayed in people with mental disorders, as the spread of the cancer at diagnosis was not different between people with or without mental illness. However, despite this, a lower survival rate after cancer diagnosis was still found in people with severe mental disorders, suggesting that research should focus on the care received after diagnosis.

Therefore, a new data linkage has now been set up which brings together information from CRIS with cancer records, Hospital Episode Statistics (HES), and mortality records from the National Cancer Registration and Analysis Service (NCRAS).

The NCRAS, run by Public Health England (PHE), collects information about every patient diagnosed with a malignant tumour in England in order to support public health, service monitoring, and research. The NCRAS collects information on over 300,000 cases of cancer every year, including detailed data about the type of cancer, how advanced it is, and the treatment the patient receives. In collaboration with PHE, the CDLS have linked CRIS to cancer data from the NCRAS along with information on hospital visits from HES, and mortality data.

Improving cancer detection and care

The CDLS holds anonymised cancer data on all South London and Maudsley NHS Foundation Trust (SLaM) service users who have received a diagnosis of cancer anywhere in England. In addition, the CDLS also holds anonymised cancer data on the residents of the four London boroughs which form the SLaM catchment area; Southwark, Lambeth, Lewisham and Croydon.

This will enable us to investigate in more detail the care received by people with mental disorders after a cancer diagnosis and the outcomes people experience, in order to investigate whether differences in these might explain differences in cancer survival. By generating information on improving cancer detection and care for people with mental illness in the UK, this project aims to enhance mental healthcare among cancer patients - whether or not they have an existing mental disorder, and improve the quality of end of life care for people with comorbid cancer and mental disorders.

More information and opting out

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

The Child and Family Court Advisory and Support Service (CAFCASS) represent children in family court cases in England. They operate within the law set by Parliament (Criminal Justice and Court Services Act 2000) and under the rules and directions of the family courts, and they are independent of the courts, social services, education and health authorities and all similar agencies. It is CAFCASS’s duty to safeguard and promote the welfare of children going through the family justice system.

CAFCASS collect data on family court cases that they are involved in, including:

  • the number of cases where the court has asked CAFCASS to carry out work in private law cases;
  • the number of care order applications made by local authorities;
  • the length of time taken to complete care and supervision proceedings;
  • and the rate of care order applications by local authorities.

Understand the mental health needs of mothers

CRIS has been linked with CAFCASS data to enable researchers to understand the mental health needs of mothers involved in care proceedings (family court cases where the council applies to have a child removed from parental care due to serious concern over their health or wellbeing).

Mothers whose children are placed into public care or adoption often have high levels of health needs, such as drug and/or alcohol misuse, exposure to violence, mental health problems as well as chronic physical conditions. However, information is lacking on how health services address these needs. This linkage will enable researchers to determine the needs of mothers before, during and after care proceedings by using longitudinal data on mental health service use.

More information and opting out

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

The Department for Work and Pensions (DWP) is responsible for welfare, pensions, and child maintenance policy within the UK; they collect information on a range of different key state benefits, for example Employment and Support Allowance (ESA), Permanent Injury Benefits (PIB), and Job Seekers Allowance (JSA).

The CDLS has linked CRIS to data from the DWP; this linkage includes important anonymised information on benefits received, as well as details of any programmes attended, such as work support schemes.

Studying mental health policies

This linkage is the first between NHS health records and DWP data. The main purpose of this project is to examine the effect of welfare reform and current assessment policies on mental health recovery and relapse: this would include examining the impact of potentially positive events (engagement in a work support packages) and negative events (regular work capability assessment, benefit sanctions, and the reduction or removal benefits) on a patient’s mental health.

The linkage between CRIS and the DWP is important because a large percentage of adults seek psychiatric help for symptoms which impact heavily on their ability to work.

Understanding patients’ benefit and occupational needs is essential to ensuring that people with mental disorders receive the best possible care. This linkage will help to provide high quality research outputs that examine the interface between mental health, work and welfare. Ultimately, this will provide much needed evidence to direct occupational health and welfare policy initiatives.

Results will be fed back to relevant organisations such as the Department of Health and the DWP, and promoted locally with the aim of directly impacting patient care, through informing changes to NHS and government benefit policies.

More information and opting out

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

The HIV and AIDS reporting system (HARS) was developed by Public Health England (PHE) in conjunction with the Department of Health and the Clinical Reference Group for HIV.

All outpatient HIV service providers submit data to HARS on a quarterly basis. HARS contains clinical data on all people diagnosed with HIV in England and this information is used to monitor the quality of care provided to people with HIV, support the commissioning of HIV services, and increase the efficiency and quality of HIV monitoring.

The CDLS has linked HARS to CRIS and currently hold anonymised HARS data for patients of the South London and Maudsley NHS Foundation Trust. This data linkage provides a resource for investigating the health care of people with HIV and mental disorders, with the aim of improving the care that they receive.

HIV and severe mental illness

HIV in people with severe mental illness (SMI) is an incredibly under-researched area in the UK, therefore, research is needed to examine the prevalence of HIV in people with SMI, the identification of at risk groups, parity in treatment and testing compared to the general population, and clinical challenges (e.g. adherence to medication).

Linking mental health data from CRIS with information on HIV from HARS will allow us to answer questions about risk and clinical picture both in terms of HIV status and mental health status. This work has the potential to highlight areas of need in treatment and prevention of HIV in people with SMI.

Findings of the research will be fed back to relevant organisations such as NICE and promoted locally with the aim of directly impacting NHS policies and current patient care.

More information and opting out

Download the CRIS-HARS Leaflet or Poster for more information.

No identifiable information is available to clinicians and researchers, all information within the linked data remains anonymous at all times. If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

By law, fertility clinics have a duty to submit data to the Human Fertilisation and Embryology Authority (HFEA) about fertility treatments taking place and babies born as a result. The HFEA hold this data on a secure database, which is the longest running database of its kind in the world. This register collects data on more than 75,000 treatments that take place in UK fertility clinics each year.

The CDLS has linked the HFEA database to CRIS and currently holds anonymised HFEA data for female patients of the South London and Maudsley NHS Foundation Trust who have also undergone fertility treatment within the UK.

We believe it will be the first undertaking of its kind to demonstrate the use of routinely collected mental health and fertility treatment data in order to understand the two-way relationships between infertility/fertility treatments and the treatment/outcome of mental health disorders.

By undertaking this linkage, and subsequent research projects, it will provide a strong evidence-base to improve understanding of people’s risks and experiences, informing service improvement, and guiding targeted intervention to improve outcomes and experiences of women undertaking fertility treatments.

More information and opting out

If you have any questions or would like to notify us that you do not wish to have your records in CRIS and/or linked with the above datasets, please contact:

CRIS Administrator, Centre for Translational Informatics, 3rd Floor, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, Denmark Hill, London, SE5 8AZ

Or email: cris.administrator@slam.nhs.uk

Service User and Carer Advisory Group

The CDLS, in collaboration with colleagues in the CRIS team have set up a Data Linkage Service User and Carer Advisory Group. The group is a regular meeting of people with lived experience of mental illness, all of whom have an interest in mental health research involving data linkage.

The group meets on a quarterly basis and researchers are invited to present their project, where they will receive feedback and advice from members. If you would like to know more about the group, please contact Amelia Jewell (amelia.jewell@slam.nhs.uk).