The Scottish electronic diabetes register and cancer registry and their linkage

1. The Scottish electronic diabetes register and cancer registry and their linkage Sarah Wild, University of Edinburgh Thanks to David Brewster, Director of the Scottish Cancer Registry June 2010

2. Background - Scotland • Population approximately 5.1 million people, 14 Health Boards • Health data identified using Community Health Index which is used for routine linkage of hospital admissions, cancer registrations and mortality records • Prescribing data available from primary care records – encashment data from pharmacies available soon

3. Background – diabetes register • Scottish Care Information – Diabetes Collaboration (SCI-DC) is an electronic population-based diabetes register populated by daily downloads from primary and secondary care systems, including prescribing • Data collection started in Tayside and Lanarkshire with national data collected from 2000 onwards • Core data set includes demographic and relevant clinical data – completeness >95% (except ethnicity) • Access for research through Scottish Diabetes Research Network (SDRN) epidemiology group

4. Number of people included in the Scottish electronic diabetes register Source: Scottish Diabetes Survey 2009

5. 2008 data extract Data available for approx 270,000 people Based on people with data on age, sex and SIMD recorded on SCI-DC who were alive in April 2008 (approx. 204,000 of 209,000) there were: • 26,242 people with T1DM (crude prevalence 0.51%) • 177,783 people with T2DM (crude prevalence 3.46%) GROS 2008 population estimates used for denominator

6. Validation of recorded type 1 diabetes and prevalence

7. Age and sex standardised prevalence of type 2 diabetes by Scottish Index of Multiple Deprivation quintile

8. Background – cancer registry • Cancer data collected since 1958 with full dataset including stage, (for breast, colorectal and cervical cancer) and information on treatment for all patients collected from 1997 • Approx. 40,000 registrations/ year • Total of over 1,200,000 records • Data quality monitored using routine indicators, computer validation, data exchange with specialist tumour registries and ad hoc studies of data accuracy and completeness of ascertainment. 

9. Collection of Scottish Cancer Registry data • Electronic capture and reformatting of ‘raw’ data • Probability matching to related incoming records and to previous registrations • Application of multiple primary rules and rules to deal with metastatic disease • Creation of ‘best guess’ provisional registrations • Completion and validation by staff based in hospitals using medical records at least 6 months after date of diagnosis

10. Source data • Hospital discharge records • Radiotherapy, oncology, haematology • Pathology records (8 different lab systems) • Mortality records • Cancer audit data (not for all cancers) • Other, eg paper records from private hospitals • Deaths from General Register Office for Scotland

11. Invasive cancer of the cervix uteri in Scotland Age-standardised incidence and mortality rates per 100,000 person-years at risk by SIMD 2006 category

12. Oesophageal adenocarcinoma in UK women: results of a case-control study Source: Cheng et al. Br J Cancer 2000; 83: 127-32

13. Factors influencing population-based survival data Data quality factors Tumour-related factors Completeness of ascertainment Extent of disease Accuracy of registration Site (and subsite) of tumour Completeness of follow-up Morphology ‘Death certificate only’ registrations Tumour biology Host factors Health care-related factors Age Screening Sex Diagnostic facilities Race/Ethnicity Treatment facilities Co-morbidity Quality of treatment Socio-economic status Follow-up care Behaviour (including awareness of cancer symptoms and compliance with treatment)

14. Linkage pilot (2005 data, 2 Health Boards): validation of diabetes recording • 47% of 82,958 hospital records after a diagnosis of diabetes include a mention of diabetes (71% of SMR01 records for MI after diagnosis of diabetes) Of the 4,777 death certificates, 9.6% gave diabetes as the underlying cause of death and a further 39% mentioned diabetes as a contributory cause

15. Background to linkage project • The Scottish Government Health Department funded the linkage of 2008 SCI-DC data to cancer (2007) and hospital admission/mortality (2008) data. • Ethical and Caldicott guardian approval obtained • Early work based on improving quality of data on date of diagnosis, type of diabetes, prescribing data, glargine & cancer • Further linkages to renal register, maternity records, hepatitis C register

16. Characteristics by treatment group

17. Risk of cancer by treatment group aModel 1 adjusts for prior cancer, type of diabetes and calendar year, and is stratified by sex ; timescale is age bModel 2 further adjusts for baseline metformin, sulfonylurea and other oral hypoglycaemic drugs at baseline cModel 3 further adjusts for diabetes duration, HbA1c, diastolic BP, systolic BP and deprivation quintile dModel 4 further adjusts for smoking ever and BMI, but note the reduction in available sample size

18. Cancer registrations and deaths in 2008 Scottish diabetes linked data Only includes first registration of each cancer in an individual person. Includes ICD-9 codes 140-239 EXCEPT 173; ICD-10 codes C00-C97 EXCEPT C44

19. Distribution of cancer registrations by type/date of diagnosis of diabetes

20. Number of site specific cancers following diagnosis of DM

21. Acknowledgements • SCI-DC data are available for analysis by members of the Scottish Diabetes Research Network thanks to the hard work of numerous NHS staff who enter the data and people and organisations (the Scottish Care Information –Diabetes Collaboration [SCI-DC] Steering Group, the Scottish Diabetes Group, the Scottish Diabetes Survey Group, the managed clinical networks managers and staff in each Health Board) involved in setting up, maintaining and overseeing SCI-DC . • Financial support for the work was provided by the Scottish Government and the Wellcome Trust through the Scottish Health Informatics Programme