# Presentation: 087303

## Patient Identifiers:The Link with New Medical Knowledge

- Christopher G. Chute, M.D., Dr.P.H.
- Professor of Medical Informatics
- Associate Professor of Epidemiology
- Mayo Foundation
- Rochester, Minnesota
*NCVHS Subcommittee on *
*Standards and Security*

## Health Care Is An Information Intensive Industry

- Control of Health Care Costs ...
- Improved Quality of Care ...
- Improved Health Outcomes ...
- Appropriate Use of Health Technology...
- Compassionate Resource Management...
***...*** ***depend upon information***
***... ******Ultimately Integrated Patient Data ***

## New Healthcare KnowledgeThe Driving Force

- What	Data Linkage
- How	Patient Identifier
- Why	To Learn about:
- Disease Natural History
- Treatment Responses
- Functional Outcomes
- Effectiveness, Efficiency, and Satisfaction

## Premises

- Absence of a common patient identifier compromises the efficient and efficacious delivery of care to an individual.
- New Insights which Expand our Knowledge about Health and Disease Require Data Linkage (Identifiers)
*Data* Security is Possible and Required

## Perspective

- What do you (we) want to know when we visit a healthcare facility:
- Anything wrong?
- What does it mean?
- What can we do about it?
- Derives from (Unbiased) Analyses of Patient Experiences.

## Episodic vs. Longitudinal Data:Anecdote vs. Information

- American Health Care is Highly Fragmented
- Decentralization of Specialties and Services
- Highly Mobile Workforce and Corresponding Coverages
- Ineffective Information Transfer
- Clinical Decisions and Research Premised upon Incomplete Information

## Clinical Episodes:Missing or Erroneous Information

- Results from Labs, X-Rays, Studies, ...
- Generated by Free Standing Contractors With Idiosyncratic Enumeration (Local Ids)
- May Not Be Merged With Clinical Record Used As Basis of Diagnostic and Treatment Decisions (Omission)
- May Be Inadvertently Merged With Wrong Record (Comission)

## Outcomes Research:

- Papilloma Virus and Cervical Cancer
- Events separated by 20-30 years
- Multiple Providers, Geographic History
- Detail Rarely Transferred
- Natural History of Chronic Conditions
- Incidence and Prevalence of Disease
- Under-reported by Hospitals and Public Health

## Population Based Research:Complete, Unbiased Experience

- Biased Hospital Based Studies
- Immediate, Episode related Information
- Skewed Representation of patients
- Socio-economic Referrals
- Non-representative Health Profiles (sick)
- Population Based Alternative
- Rochester Epidemiology Project

## Rochester Epidemiology Project

- NIH Funded Study of Health and Disease in Free Living Population
- Begun 1966
- Over 1,000 Peer Reviewed Publications
- Integrates Health Experience Across All Providers for Persons in Olmsted County, MN.

## Rochester Epidemiology Project:Logistics

*De facto* Master Patient Index Approach
- Know Well its Limitations and Inaccuracies
- Cooperation of all Providers in Region
- Master Diagnostic and Procedure Index
- Highly Secure Data Format
- Restricted Access
- Encrypted Communication of **DATA**

## Rochester Epidemiology Project:Benefits

- First Resource to Unequivocally Demonstrate Hospital Biases
- Natural History of Disease Differs in Hospital Series from that in Community
- Hospital Series Patients Tend to Be Sicker
- First Example: Multiple Sclerosis 1950
- Double Prevalence cited at time
- Vastly Better Prognosis

## Rochester Epidemiology Project:Benefits

- First Resource to Unequivocally Demonstrate Distance Referral Biases
- Patients Referred from Distant Sites fare Much Better [Able to Travel]
- Local Patients Present with More Advanced, Less Treatable Disease

## Mayo LegacyPatient Data as Valued Resource 

- Why did Mayo emerge from MN cornfields?

- Heritage of Organizing, Preserving, and Linking Patient Data
- Medical Record Structures: 1907
***Common Identifier to Facilitate Linkage***
- Commitment and Resource to Indexing
- 5x7 Cards by Disease and Procedure: 1909

## Mayo Record

- During
- 91 years of continuous use
- over 5.5 million patients
- conducting over 4,000 studies per year
- Mayo has no record of confidentiality breached by research projects accessing patient data.

## Special Concern

- Confidentiality

- Overriding Concern: Welfare of the patient

## Whither Anonymous?	

- Adequate for final analyses of linked data
- Linkage process *per se* precludes complete anonymity.
- Computer only knowledge (encryption?)
- Distinctions surround when the key is broken - application specific.
- Immediately for Epidemiology
- Never for clinical care

## It’s the Data, Folks(not the Obscurity of an Identifier)

- Encryption
- Exclusive Health Application
- Shielding
- Incorporation of Personal Characteristics
- Public Access (but private application)

## On Check Digits 

- Useful Service
- Data integrity when humanly keyed
- Adequate Algorithm
- Sufficient to detect adds, deletes, inversions
- Typically factored by discreet prime numbers
- Length
- Function of how sure (1 in 10; 1 in 342)

## Why Have a Unique Identifier?

- To Facilitate Data Linkage, in Direct Support of an Individuals Care, and Indirectly by Acquiring New Healthcare Knowledge From Aggregate Patient Experiences.

## How to Improve Upon IDs in Use Today?

- By Making Them Standardized, Consistent, Comparable, and Interchangeable.  There Are Grave and Conceivably Fatal Implications to Multiple Identifiers for a Single Individual.

## Viable Alternatives?

- Business As Usual.
- Huge Opportunity Cost to Society and Persons
- Engage Master Patient Indices
- Substantial Room for Error and Mistreatment
- Very Large Cost to Create and Maintain
- Virtually Impossible for Data Interchange

## Impact on Privacy?

- The Identifier Would Have No Impact on Privacy.  It Is the Health Data Which Is Sensitive.  Implementing an Identifier Must Be in Tandem With Policies and Legislation Ensuring Privacy.

## How should the Government be Involved?

- Logical Broker for Establishing, Issuing, Maintaining, and Overseeing Health Identifiers.
- Monitor Appropriate Patient Data Use Via Policy and Audit.

## 2nd to the Last Word

- A Common Health Identifier Would Ultimately Serve the *Best Interests of Individual Patients* Through Better Integration of Their Care and Enabling Observational Research on Health Outcomes.

## Last Word

- If Fairly and Intelligently Implemented, Electronic Patient Records Using Common Patient Identifiers Might Actually *Reduce Risks to Patient Confidentiality* Relative to What Exists in Today's In-auditable Paper Environment.

## Christopher G. Chute MD, DrPH
Professor of Medical Informatics
Associate Professor of Epidemiology
Head, Section Medical Information Resources
Mayo Clinic/Foundation
Rochester, MN  55905

- Professor of Medical Informatics
- Associate Professor of Epidemiology
- Head, Section Medical Information Resources
- Mayo Clinic/Foundation
- Rochester, MN  55905

- Ph: 507 284 5541
- Fx: 507 284 1516
- Em: chute@Mayo.edu