Danish population-based registries in cancer pharmacoepidemiology. Cancer Pharmacoepidemiology Meeting Dublin September 2013

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1 Danish population-based registries in cancer pharmacoepidemiology Deirdre Cronin Fenton Cancer Pharmacoepidemiology Meeting Dublin September 2013

2 Frank L. Science 2003

3 The Danish Cohort

4 The Civil Personal Registration Number A unique personal identification number encoding gender and date of birth Assigned to all Danish residents at birth or emigration Used in all medical contact...and everywhere else also The CPR number Birth day Birth month Birth year even=f odd=m

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6 Danish Civil Registration System Established on April 2, 1968 Greenland since 1972; no registration for Faroe Islands Data registered: CPR-number, name, sex, date & place of birth, residence, citizenship, vital status, CPR-number of parents and spouses variables Updated daily The CPR number Birth day Birth month Birth year even=f odd=m

7 The CPR number Danish Cancer Registry Clinical Databases Danish National Registry of Patients CPR# Pathology Archives Danish Civil Registry Prescription Databases

8 Cancer Databases in Denmark

9 Danish Cancer Registry Established 1943/compulsory reporting since 1987 Incident cases of carcinomas, sarcomas, leukaemia, lymphoma, myeloma and mycosis fungoides Tumor-like neoplasms and benign tumors: papillomas of urinary tract, benign CNS tumors, carcinomas in-situ at cervical biopsy or smear Selected key variables: CPR number Date of diagnosis and method of verification Extent or spread of tumor Treatment up to 4 months after diagnosis

10 Danish National Patient Registry Est. 1977, updated thro 2012 All admissions to public hospitals in Denmark (since 1995 outpatient and emergency visits) Selected key variables Patient CPR number Dates of admission and discharge Up to 20 diagnoses (ICD-8 through 1993/ICD-10 thereafter) Hospital-administered medications Hospital and department codes (specialty)

11 Clinical Cancer Databases Urological cancers Ovarian cancer Colorectal cancer Non-melanoma skin cancer...many others

12 Danish Breast Cancer Cooperative Group Registry Est to ensure optimal diagnosis and treatment of operable primary breast cancer in Denmark >90% of Danish breast cancer cases; >50% on clinical trials Detailed information on clinical & treatment characteristics, and follow-up Standardized data collection from clinical dept directly to DBCG Generalizability of population-based setting with data quality advantages of a clinical trial

13 Pharmacoepidemiologic research in Denmark

14 Pharmacoepidemiology studies in Denmark The Prescription Registries of the Northern and Central Danish Region (Aarhus University AUPD) The Odense University Pharmacoepidemiological Database (OPED) The Danish National Prescription Registry at Statistics Denmark Enable compilation of longitudinal drug histories and linking of prescription data to other population-based registries in Denmark

15 COMPARISON OF NATIONAL AND AUPD PRESCRIPTION DATA National Prescription Database Aarhus University Prescription Database Administered by Statistics Denmark Department of Clinical Epidemiology, AU Population covered Entire Denmark Two regions since s Entire Denmark since 2004 Period covered Since 1994 Since (depending on area) Records reimbursed prescriptions Non-reimbursed prescriptions Hospital drug dispensations Yes, both generally and conditionally reimbursed Yes Aggregate only CPR deleted Yes No Yes, both generally and conditionally reimbursed No (e.g., oral contraceptives, benzodiazepines) No

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17 Population facts "The Danish regions in brief (

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19 Network of Population-based Registries COUNTY PRESCRIPTION REGISTRY NSAIDs, scox-2 inhibitors newer & older Aspirin (low & high dose) HRT Population controls (n=81,950) CPR# CIVIL REGISTRY Danish National HOSPITAL Registry DISCHARGE of REGISTRY Patients Co-morbidities Breast cancer cases (n=8,195)

20 Drug Exposure Ever (>3 pres.) versus never/rare use Temporality of use: Recent users: >3 pres. within 2 yrs of index Former users: <3 pres. within 2 yrs of index or >3 pres. for all yrs Intensity: Low, Medium, High # prescriptions / total duration Duration: Short-term & Long-term # days from date of 1 st to last pres. + duration of last pres. 20

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26 The Danish National Prescription Database

27 National Prescription Registry Established 1994 Individual outpatient dispensations Aggregate hospital sales Selected key variables Patient CPR number Dispensed drug (ATC code) Date of dispensation Universal Nordic product number, encoding package, formulation, number of pills and DDD Administered by Statistics Denmark

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29 Statins & Breast Cancer Recurrence Aims: To measure the association between statin use and the rate of breast cancer recurrence To examine this association by Statin solubility (lipophilic versus hydrophilic) Site of breast cancer recurrence Clinical & treatment factors Hypothesis: Use of lipophilic statins, but not hydrophilic statins, is associated with a decreased rate of breast cancer recurrence compared with non-use of statins

30 Study population & data sources Danish population-based cohort study Stage I-III breast cancer (n=18,769; n=3,419 recurrences) Diagnosis & registered in DBCG Danish National Prescription Database: prescription data Danish National Registry of Patients: comorbid diseases 10 years of follow-up or through 31/12/2008 Ahern et al., 2011

31 Definition of statins exposure Statins exposure: >=1 prescription each year after diagnosis Lipophilic versus hydrophilic Duration (years of exposure) & intensity of use (# of prescriptions) Comedications: aspirin, NSAIDs, ACE-inhibitors, vitamin K anticoagulants during follow-up, and pre-diagnosis HRT Ahern et al., 2011

32 Statistical Analyses Crude and adjusted Cox proportional hazards regression with drug exposure as time-varying covariates lagged by one year Stratified by clinical & treatment factors Generalized linear regression models Adjusted risks and risk differences Ahern et al., 2011

33 Results 3282 statin users 2524 (77%) lipophilic statins only 92% simvastatin 206 (6.3%) hydrophilic statins only 552 (17%) switched categories (excluded) 3419 recurrences in 114,006 py Median follow-up = 6.8 yrs Ahern et al., 2011

34 Characteristics of the study cohort Total n=18,769 Menopausal status Pre Post UICC Stage I II III Histologic grade Low Moderate High ER/endocrine therapy ER+/ET+ ER-/ET- ER+/ET- ER-/ET+ Statin Users 514 2,768 1,352 1, , , Subjects, n (%) (16) (84) (41) (45) (14) (36) (44) (20) (52) (17) (30) (0.3) Non-Users 5,077 10,407 5,836 6,663 2,982 4,109 5,414 3,088 6,654 3,240 4, (33) (67) (38) (43) (19) (33) (43) (24) (45) (22) (33) (0.2)

35 Statin prescription & breast cancer recurrence Exclusive Simvastatin: Adj. 10-year risk difference = (95% CI= -0.11, -0.08) Adj. HR = 0.70 (95% CI= 0.57, 0.86) Hydrophilic statins: Adj. 10-year risk difference = 0.05 (95%CI= -0.01, 0.11) Adj. HR = 1.2 (95% CI = 0.79, 1.7) Ahern et al., 2011

36 Statin prescription & ten-year breast cancer recurrence Breast cancer recurrences by statin use Recurrences/ person-years Unadjusted Hazard Ratio (95% CI) Adjusted Hazard Ratio (95% CI) Ten-year recurrence: Never prescribed a statin Any statin Only hydrophilic Only lipophilic Only simvastatin 3,170/ 249/ 39/ 182/ 166/ 88,384 12, ,263 7, ref 0.87 (0.75, 1.0) 1.2 (0.83, 1.7) 0.86 (0.73, 1.0) 0.83 (0.69, 0.99) 1. ref 0.83 (0.70, 0.98) 1.2 (0.79, 1.7) 0.73 (0.60, 0.89) 0.70 (0.57, 0.86) Only hydrophilic Only lipophilic Only simvastatin 39/ 182/ 166/ 951 8,263 7, ref 0.69 (0.47, 1.0) 0.65 (0.43, 0.96) 1. ref 0.59 (0.39, 0.91) 0.55 (0.35, 0.85)

37 Simvastatin prescription versus never prescription Stratified models Recurrences, n (%) Adjusted Hazard Ratio (95% CI) Estrogen receptor status Negative Positive 862 2,309 (27) (73) 0.75 (0.47, 1.2) 0.69 (0.55, 0.88) Histologic grade Low Moderate High 608 1, (22) (45) (33) 0.59 (0.39, 0.89) 0.75 (0.55, 1.0) 0.76 (0.51, 1.1) Type of primary therapy Mastectomy, no RT Breast-conserving surgery, with RT 1, (65) (35) 0.72 (0.54, 0.96) 0.68 (0.46, 1.0)

38 Simvastatin prescription versus never prescription Recurrence site-specific models Recurrences, n (%) Adjusted Hazard Ratio (95% CI) Bone Contralateral breast Ipsilateral breast Lymph node Lungs and pleura Liver Central nervous system All other sites 1, (33) (16) (17) (16) (8.8) (6.1) (2.0) (2.7) 0.91 (0.65, 1.3) 0.54 (0.33, 0.90) 0.57 (0.32, 1.0) 0.56 (0.31, 1.0) 0.67 (0.34, 1.3) 0.96 (0.40, 2.3) 0.60 (0.08, 4.7) n/a

39 Strengths Large size & prospective data High quality registry data DBCG National Registry of Medicinal Products Danish National Registry of Patients Information on site of recurrence & clinical factors Lipophilic versus hydrophilic statins Ahern et al., 2011

40 Limitations Prescription compliance Prescriptions retrieved at pharmacy No information on bodymass index Confounding by indication Hypercholesterolemia? Ahern et al., 2011

41 Conclusions Lipophilic statins, but not hydrophilic statins, are associated with a decreased risk of breast cancer recurrence

42 Statins & Breast Cancer Recurrence % Citation RR (95% CI) ES (95% CI) % Weight Kwan et al., (0.39, 1.14) 0.67 (0.39, 1.14) 8.28 Chae et al., (0.24, 0.67) 0.40 (0.24, 0.67) 8.90 Ahern et al., (0.70, 0.98) 0.83 (0.70, 0.98) Overall 0.76 (0.66, 0.89) 0.76 (0.66, 0.89) RR & 95% CI (log scale)

43 Implications of the statins paper... Statins & recurrence in other cancers? Clinical trial of simvastatin & breast cancer recurrence DBCG

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48 The Department of Clinical Epidemiology

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50 Klinisk Epidemiologisk Afdeling (KEA) Research Cancer Pharmacogenetics Pharmacoepidemiology Cardiovascular diseases Gastrointestinal diseases Infectious diseases Critical care Reproductive epidemiology

51 Information on Danish Registry Sources Use of Medical Databases in Clinical Epidemiology Sorensen, Christensen, Schlosser, Pedersen (Eds) See: Clinical Epidemiology (free online journal) Special Danish registries edition: 2010

52 Acknowledgements KEA: Henrik Toft Sørensen, Lars Pedersen, Lone Winther Lietzen, Gitte Vrelits Sørensen, Anders Riis Vera Ehrenstein Emory University: Tim Lash Harvard & U. Vermont: Tom Ahern DBCG: Peer Christiansen, Jens Peter Garne

53 Funding Danish Cancer Society Karen Elise Jensen Foundation Danish Cancer Research Foundation Elvira og Rasmus Riisforts Fond Vest Dansk Forsknings Fond The Clinical Institute, Aarhus University The Department of Clinical Epidemiology Research Foundation Danish Medical Research Council US National Cancer Institute

54 Mange tak!