EPI 5240: Introduction to Epidemiology Sources of Information; Disease Registries September 21, 2009

1. EPI 5240:Introduction to EpidemiologySources of Information; Disease RegistriesSeptember 21, 2009 Dr. N. Birkett, Department of Epidemiology & Community Medicine, University of Ottawa

2. Session Overview • Overview sources of information about mortality/morbidity in Canada. • Review design of disease registries • Provide examples of registries in Canada.

3. Sources of data: Mortality (1) Vital Statistics • Births, deaths, marriages, etc. • Mostly reported by physicians. • Coded centrally by staff trained to apply ICD, etc. coding. • Accuracy of information depends on initial effort by person completing the form • Multiple causes of death coding. • Timeliness of reports is getting better • 1999 used to be the most recent information published with 2004 for summary mortality data on-line (CANSIM). • Now can get data up to about 2007.

4. Sources of data: Mortality (2) Canadian Mortality Data-base • Information from all Canadian death certificates from 1950 to present. • Death certificates (and birth certificates) used to be publicly available but are not now. • CMDB can be searched electronically (for a fee) to link subjects to mortality records • ‘GIRLS’ • Completeness is very good; mainly misses out-of-country deaths.

5. Sources of data: Morbidity (1) • Much harder to get information and much less complete (e.g. many diseases/conditions have no routinely available information) • Good information on • Many infectious diseases • Cancer • Abuse and violence • Some information, but lower quality, on: • Congenital abnormalities • Vision problems • Diabetes • Surprisingly poor information on CHD incident cases.

6. Sources of data: Morbidity (2) • Potential sources of information • Disease registries • Surveillance • Reportable diseases • Administrative data • CIHI • ICES • Saskatchewan Drug Programme • ADRs • General population surveys • Special targeted surveys

7. Sources of data: Morbidity (3) Disease surveillance • The PHAC runs a large number of surveillance programmes. • Influenza (fluwatch) • HIV • Injuries • West Nile disease • Extends to chronic diseases as well.

8. Sources of data: Morbidity (4) Disease surveillance • Potential Biases • Incomplete coverage • Method of disease identification • Self report • self diagnosis • Lack of confirmatory tests • Popularity effects • H1N1 • Child abuse • Can pick up epidemics but does not give valid incidence rates • ‘start’ of an epidemic can enhance reporting leading to artefacts in size of epidemic • Sentinel Practices • Provincial health labs • Ontario Agency for Health Protection and Promotion

9. Sources of data: Morbidity (5) Disease surveillance • Reportable Diseases • Another way to conduct surveillance • ‘active’ • MD’s must report (by law) any diagnosis of these conditions • Applies mainly to infectious diseases • Also applies to • suspected child abuse. • Gun shot victims in hospitals (Ontario) • Many professional duties • E.g. drug abuse in MD’s.

10. Sources of data: Morbidity (5) CIHI (Canadian Institute for Health Information) • An independent, not-for-profit organization that provides essential data and analysis on Canada’s health system and the health of Canadians • URL: http://secure.cihi.ca/cihiweb/dispPage.jsp?cw_page=home_e • Manages multiple data bases • Health Human Resources • Health Spending • Health Services • Multiple sources of information including hospital discharges.

11. Sources of data: Morbidity (6) CIHI (cntd) • Sample databases: • Canadian Medication Incident Reporting and Prevention System • Continuing Care Reporting System • Discharge Abstract Database • Home Care Reporting System • Hospital Mental Health Database • Hospital Morbidity Database • National Ambulatory Care Reporting System • Therapeutic Abortions Database • National Health Expenditures Database • National Prescription Drug Utilization Information System • Largely based on discharge diagnoses and information

12. Sources of data: Morbidity (7) CIHI (cntd) • Sample registries: • Canadian Joint Replacement Registry • Canadian Organ Replacement Registry • Linked to kidney registry • National Trauma Registry • Ontario Trauma Registry

13. Sources of data: Morbidity (8) Clinical Data: OHIP, etc. • Contains information included in CIHI but also information on clinical encounters outside hospital • ICES – Institute for Clinical Evaluative Services • Funded by Ontario government • Aim is to improve delivery of health care Ontario residents. • Can collaborate with outside groups but strong security restrictions on access to data.

14. Sources of data: Morbidity (9) Surveys • Can be targeted at specific conditions (e.g.. Canadian Hypertension Survey) or more general (e.g. National Population Health Survey) • Most recent surveys in Canada have based on self-reported data • Inaccurate/incomplete diagnoses • Focus on risk behaviours and psychosocial factors

15. Sources of data: Morbidity (10) Surveys • Nutrition Canada Survey (1970-72) • Canada Health Survey (1978) • Canadian Heart Health Survey (1988-92) • Canadian Study on Health and Aging (1992) • NPHS (1994, 1996/6 & 1998/9) • Includes a cohort follow-up component

16. Sources of data: Morbidity (11) Surveys • Canadian Community Health Survey • Started in 2000 • Health determinants • Health status • Health services utilization • 2 year cycle • 130,000 subjects in year 1 of cycle • 35,000 subjects in year 2 of cycle • No physical measures

17. Sources of data: Morbidity (12) Surveys • Canadian Health Measures Survey • N=5,000 • Physical measures • Anthropometry • Cardio fitness • Musculoskeletal fitness • Physical Activity • Spirometry • Oral Health • Blood and urine sample • ‘in the field’: 2006-8

18. Sources of data: morbidity (13) Surveys • Canadian Cohort Studies • A number of large-scale cohorts are just getting started. • Cancer • CHD • Healthy Aging • Childhood development

19. Registries (1) • A list or database of people with a pre-defined condition or illness • Ideally, will include ALL people with the condition • Often, will only contain a sub-set. • Population-based vs. clinic/hospital/etc. based • ‘Population-based’ defines a target population and registers all cases arising from that population • Instead, register all cases treated at a hospital/clinic. OR ask for volunteers with a disease • Most useful for looking at prognosis

20. Registries (2) Some Methodology Issues • Definition of disease state. • Classification ‘rules’. • What to do when the ‘rules’ change? • Need for standard diagnostic criteria/tests • Validity of diagnosis • False positives • False negatives. • Example: Cancer • Malignant vs. benign vs. in-situ • Are some cancers excluded • non-melanoma skin cancer • Primary vs. metastatic disease • First vs. second (and later) cancers

21. Registries (3) Some Methodology Issues (cntd) • Completeness of capture • Applies more to population based registries • Representativeness of registered subjects • Applies more to non-population based registries • Methods of capturing information required on each subject. • MD information • Ethical issues; response rate • Patient contact • Response rate; validity (and knowledge) of information • Charts, lab reports, etc.

22. Registries (4) Subject Identification • Passive vs. active vs. Other. • Passive • Subjects identified using existing records with no active reporting by MD, patient, etc. • Active • MD required to report any one with the diagnosis • HIV, reportable diseases • Other • Volunteers • Members of patient support groups • CNIB • Canadian Diabetes Association

23. Registries (5) What data to collect? • Depends on purpose of the registry • Subject ID information • Unique identifiers are ‘best’ • Not in Canada • Record linkage • Demographic information • Age, sex, address, date of birth • Diagnostic details • ICD codes • Lab tests • Follow-up • Treatments used • Responses and Relapses • Vital Status • Lab tests

24. Registries (6) Uses of Registries • Descriptive epidemiology of disease • Incidence/mortality rates by age, sex, etc. • Trends in incidence/mortality • Generate etiological hypotheses • Prognosis • Source of subjects for studies of etiology and prognosis • Ethical/privacy issues

25. Registries (7) Registries: Cancer • Under provincial jurisdiction • Mostly, passive identification • Electronic reporting of new cases. • Cancer registration is mandated by law • Since 1969, all provinces send data to Statistics Canada for entry in Canadian Cancer Registry. • Data is usually 3-4 years behind. • Hard to get access for outside researchers • Fees • Need every province to give permission. • Can be used for record linkage • Ethical and privacy issues

26. Registries (8) Registries: Congenital Diseases • BC has most extensive system (Health Status Registry) • First established in 1952 as voluntary registry of ‘crippled children’ to assist in identifying care needs. • Expanded to include genetic conditions and birth problems like rubella • Now captures cases based on hospital discharge summaries. • Good data since 1984, especially for conditions diagnosed at birth. • Alberta has a less extensive registry (age<1)

27. Registries (9) Registries: Cardiovascular Disease • No comprehensive CHD registries in Canada • Several groups have local registries of specific conditions • Acute MI patients • Pacemakers • Hard to identify cases • Clinical disease vs. atherosclerosis • Sudden death • Non-hospital treatment • Nova Scotia, Saskatchewan and BC have best information

28. Registries (10) Registries: Renal failure • Canadian Renal Failure Registry • Started in 1981. • Voluntary • Appears to have been replaced by a broader based registry collecting cases through hospital discharge summaries: • Canadian Organ Replacement Registry • Records information on vital organ transplants and dialysis patients. • Run through CIHI

29. Registries (11) Registries: Miscellaneous • Vision • CNIB used to run a voluntary registry of people who were legally blind (started in 1918) • Current status unclear. • Ottawa Eye Institute is currently doing a review of vision-related registries • Diabetes Mellitus • Montreal-based registry of IIDM started in 1981 • Canadian Diabetes Association maintains record of members but also includes family and non-patients.

30. Registries (12) Registries: Miscellaneous • Hemophillia • Canadian Hemophillia Society maintains list of people with hemophillia • Trauma, winter sports injuries, childhood injuries, etc. • Many are based on hospital discharge information from CIHI • Variable quality but can be useful. • Very limited information on mental health and conditions like arthritis

31. Summary • Good information on mortality and cancer incidence • Lack of information for several key health conditions • Heart disease incidence • Most chronic diseases with non-fatal impact (e.g.. arthritis) • Reportable diseases help monitor and control infectious diseases