Making the case for anonymization

Craig Earle, MD MSc FRCPC

Ontario Institute for Cancer ResearchCancer Care OntarioInstitute for Clinical Evaluative SciencesSunnybrook-Odette Cancer CentreUniversity of Toronto

‹#›

PATIENT

Drugs

Ministry of

Health

OUTCOMES

Cancer Control Continuum

Lab

End of

Life

Cancer

Care

Ontario

HospitalPCPSpecialist

HEALTH CARE SYSTEM

Prevention

Screening

Diagnosis

Survivorship

Treatment

COSTQUALITY

ACCESS

Health Services Research (HSR)

3

Ontario strengths for Health Services Research

• Universal healthcare

– Small private insurance sector

• Drug coverage

– > 65 yo

• Centralization of some services

– radiation

Derived chronic conditions (IKN)

People &

Geography (IKN)

Special Collections

(IKN)

Registries

(Cancer, Stoke,

CCN, *Birth outcomes)

Federal immigration register

*First Nations/Metis

(using linked data)

Diabetes

Hypertension

COPD

CHF

AMI

Asthma

IBD

Health Services (IKN)

Physician claims

In-patient hospital discharge abstracts

Emergency and ambulatory care

abstracts

Prescription drug claims

(65 and over)

Home care claimsRehab claims

Long-term care visits

In-patient mental health

data

Providers/Facilities

PhysiciansHospitals

Complex careLong-term

care homesHome care

Real-time (IKN)

*Patient functional

status*Peritoneal

Dialysis

Population Estimates

Canada Census Profiles

Linked de-identified data set for analysisPrimary

Collected Data

(IKN)

Postal CodeConversion/Geographical

Ontario Linkable Data at ICES

People in Ontario since

1985

Unique individual

anonymous #IKN

*HIV

Developmental

Disabilities

Death register

IKN=unique algorithm based on Ontario health card number

5

The Power of Data Linkage

Create cohorts focusing on continuity of care paths, diseases, outcomes of care, including some determinants of health information

Example:

• OCR gives details about cancer diagnoses

• RPDB provides demographic information

• OHIP provides information about physician service utilization

• DAD/NACRS from CIHI assessment of disease, hospital-based procedures and health service outcomes

• Census permits population estimates and impact of SES

• Survey data may add self-reported disease prevalence, health service use and lifestyle information

HSR Across the Cancer Control Continuum

Screening/

Detection

Diagnosis/

Treatment

Survivorship End of life

care

Access Colon Cancer

Check

Referral patterns

for stage IV

NSCLC

Surveillance

after breast

cancer

Aggressiveness

of cancer care

near the end of

life

Quality Colon cancer

screening rates

Effect of Volume

& MD specialty

on ovarian

cancer outcomes

Concordance

with

surveillance

guidelines

Hospice

utilization

patterns

Cost CEA of PET

staging in

esophageal

cancer

Influenza

vaccination

Resource

utilization in

follow up

Case Costing

Outcomes Screening for

2nd cancers in

Hodgkin’s

survivors

Lung cancer

surgery

regionalization

Late effects

of cancer

treatment

Complications

from continuing

chemotherapy

too near death

7

ICES

The Ontario Cancer Data

Linkage Project (‘cd-link’)

9

cd-link goals

1. To make linkages of existing data

sources available as a resource for

cancer health services researchers

2. To put de-identified linked data

directly into the hands of

researchers

10

cd-link

Procedures

Proposal

11

Data Request Form

• Define Cohort

• Datasets

– Active selection of variables

12

Data Use Agreement (DUA)

• Purpose limitation• Confidentiality/re-identification/linkage/re-contact• Security: password protection, encryption, public access,

removable media• Research ethics approval• Limitation on onward transfer/sharing with 3rd parties• Cell size suppression• Pre-publication review• Acknowledgement (not co-authorship or endorsement)• Ownership of data• Returning/destroying data• Breach notification enforcement • Responsibility to educate anyone touching the data• Signed confidentiality agreement with anyone touching

the data• Threat of surprise audits

13

HIPAA 18 restricted variables

1. Name

2. MRN

3. HIC

4. Geographic units < 20,000

5. Dates (except year)

• 6. phone #

• 7. fax #

• 8. e-mail address

• 9. SSN

• 10. license #

• 11. account #

• 12. VIN

• 13. device serial #

• 14. URL

• 15. IP address

• 16. Biometrics

• 17. photos

• 18. any other unique identifying code

“safe harbor method’

14

PARAT

cd-link de-identification

Name OHIP DOB Sex Dx DoDx Adm dt MD Census

med

income

DoD

Lynn

Foma

123456 1/7/46 F NHL 3/9/07 7/4/07 35429 61,435 9/9/07

- 95135 1946* F NHL 2007 117 5384 61,000 184

*or 5-year age groups with high and low limits

No longer PHI. Not human subjects research.

19

Assess feasibility for

cd-link

Presentation to Cancer

Program

ICES Privacy approval

DCP discussions and dataset creation

PARATBurn to DVD and courier

Client receives DVD and completes analysesData

destruction and project closure

Request Form

submittedConsultation phase

Confirmation of Feasibility

issued

Services Agreement issued; DCP discussion and dataset creation

PARAT and IDAVE

onboarding

Dataset posted to

IDAVERequestor analyses data

ICES Data & Analytic Services

DAS

cd-link

- Solves the problem of data availability outside of Ontario- Two private sector pilots underway (Medtronic & Brogan), $100K access fee

- ‘Pilot tested’ 2 releases through DAS- In the process of modifying ICES-CCO collaboration agreement to facilitate shift

to VPN

20

Future challenges

• EHR data

– Misspellings, typographic errors, variations in nomenclature

– Possibly identifying processes

• Knowledge of inclusion in data set?

• Incremental privacy breach?

• ‘De-facing’ imaging data

21

22

Future challenges

• EHR data

– Misspellings, typographic errors, variations in nomenclature

– Possibly identifying processes

• Knowledge of inclusion in data set?

• Incremental privacy breach?

• ‘De-facing’ imaging data

• Genomics

23

Conclusion

• Privacy and research are both public goods

• With the proper safeguards in place, both can be

optimized

“Positive sum (win-win) paradigm”Dr. Ann Cavoukian

(former Ontario Information and Privacy Commissioner)