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Epidemiologic Studies of Cancer, Diabetes & Its Treatments: Opportunities from Canada. Jeffrey A. Johnson University of Alberta Edmonton, Canada. Cancer & Diabetes Epidemiology Consortium June 14, 2010. Canadian Team. University of Alberta, Edmonton
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Epidemiologic Studies of Cancer, Diabetes & Its Treatments: Opportunities from Canada Jeffrey A. Johnson University of Alberta Edmonton, Canada Cancer & Diabetes Epidemiology Consortium June 14, 2010
Canadian Team University of Alberta, Edmonton Jeff Johnson Samantha Bowker Yutaka Yasui University of British Columbia, Vancouver, BC Carlo Marra
Welcome to Canada! • ~ 10 million km2 / ~3.9 million mi2 • population: ~34 million (2009) • 10 provinces, 3 territories • Health care is a national philosophy, but a P/T mandate • 13 ‘health care systems’ • All residents have publically funded insurance for ‘medically necessary’ health services (Canada Health Act) • Physician and Hospital services • Drug coverage varies (products, policy, population) • Providers send ‘bill’ to Health Ministry • Each resident has Personal Health Number
Unique ID Unique ID Unique ID Health Services Health Services Health Care & DataCanadian Context • Publically Funded, Privately Delivered Insurance Registry Hospital Physician Drug Age Unique ID Demographic Data Gender DIN DM Status Incident/Prev DM Status Incident/Prev Status Aboriginal Amt Dispensed Mortality Co-Morbidities /Procedures Co-Morbidities /Procedures Prescriber Location of Residence Vital Statistics COD ICD-9-CM or ICD-10CA ICD-9-CM
Year of Database Initiation Province Hospital Physician Drugs Alberta 1973 1973 1994 (seniors) BC 1985 1985 1997 (All) Manitoba 1970 1970 1994 (All) New Brunswick 1973 1989 1990 (Seniors) Nova Scotia 1973 1991 1975 (Seniors) Ontario 1963 1989 1994 (Seniors) Prince Edward Island 1984 1989 -- Quebec 1983 1986 1981 (Seniors) Saskatchewan 1970 1971 1975 (All)
Case Definition of DMwith Large Admin Databases • Case/Cohort Ascertainment • Identifying diabetes in admin data • National Diabetes Surveillance System Case Def’n • 2 physician visits for DM (ICD-9 250) in 2 year period • or • 1 hospitalization for DM (ICD-10CA E10-E14) • Antidiabetic Drug Use • - e.g., new users of oral antidiabetic agents
Diabetes Treatments& Cancer Mortality Retrospective Cohort Study Saskatchewan, Canada, 1991-1999 • Time fixed Cox regression analysis • Metformin use as the reference group • Insulin add-on as covariate 1.30 Sulfonylurea Monotherapy 1.90 Insulin Added Adjusted* HR: 0.5 0.9 1.0 1.3 1.8 2.0 Increased Risk Reduced Risk *age, sex, Chronic Disease Score Bowker et al., Diabetes Care, 2006
Diabetes Treatments& Cancer Mortality Retrospective Cohort Study Saskatchewan, Canada, 1991-1999 • Time varying Cox regression analysis • SU Monotherapy as the reference group • Insulin add-on dose-risk gradient Metformin Use No Insulin Ever (ref) < 3 Rx/year 3 to 11 Rx/year ≥ 12 Rx/year 0.80 2.22 3.33 6.40 Adjusted HR: 1.5 2.0 4.0 6.0 0.4 0.6 0.8 1 Increased Risk Reduced Risk Bowker SL et al., Diabetologia, 2010
British Columbia • Established in 1871 • ~ 945,000 km2 / ~ 365,000 mi2 • population: ~ 4.5 million (2010) • Diabetes prevalence1: • 4.9% (~ 200,0000) in 2006-07 • Diabetes Incidence (2006-07)1: • 5.0 per 1000 (~ 20,000 cases/yr) • Cancer Incidence 2007 (per 100,000)2: • Crude, all cancers, all ages: 532 (M) • 452 (F) • Age-std, all cancers, all ages: 438(M) • 336(F) 1 National Diabetes Surveillance System, PHAC 2 BC Cancer Agency
BC Cancer Agency Male Female
BC - DM & Cancer Cohort Study Washout CancerDM Index Period DM: NDSS case def’n non DM: sex, aboriginal match Follow-up Period 1995 1997 2002 2007 X 11 yrs X 8.5 yrs X 8.5 yrs X 4 yrs Subjects may be ‘censored’ due to: - death - leaving province - Dec. 31, 2007
BC - DM & Cancer Cohort Study
BC - DM & Cancer Cohort Study
BC - DM & Cancer Cohort Study
BC - DM & Cancer Cohort Study Source: http://www.health.gov.bc.ca/pharmacare
BC - DM & Cancer Cohort Study
Thank you for your attention…
Epidemiologic Studieswith Large BC Admin Databases • Advantages of BC Admin Dataset: • Population-based data (minimize selection bias) • Linkable databases on PHN • BC Cancer Agency data is rich • Efficient use of available data • Large populations/samples • Historic data • Disadvantages of BC Admin Dataset: • Accuracy of diagnostic codes / billing data • Incomplete information on potential confounders • e.g., lifestyle behaviours; clinical data • Limited use of new agents of interest (i.e., glargine, GLP-1)
BC Cancer Agency Male Female
Validity of DM Case Def’nin Large Admin Databases *Youden’s index = (Sens + Spec) - 1