ways to structure medical data to use in electronic health records

1. The Structure of Medical
Data
• Medicine is remarkable for its failure to
develop a standarized vocabulary and
nomenclature
• Issues of data retrieval and analysis are
confounded by discrepancies between
observers and data analysts
• Imprecission and a lack of standarized
vocabulary are problematic when we wish to
aggregate data recorded by multiple health
professionals
• EHR’s, their encoding must be able to
presume a specific meaning for the terms

2. Coding systems
 Because of the needs to know about
health trends for populations and to
recognize epidemics in the early
stages, there are various health
reporting requirements for hospitals
and physicians.
 Also reporting discharge
diagnosis, procedures performed on
pacients
 The codes used must be well defined

3. Coding systems
 Coding systems have limitations when
are applied in more general clinical
settings
 Researchers have worked to develop
a unified medical language system
(UMLS), a common structure that ties
together the various vocabularies the
have been created

4. The Data Knowledge
Spectrum
 A central focus in medical informatics
is the information base that constitutes
the substance of medicine
 Three terms are frequently used to
describe the content of computed
based systems: data, information and
knowledge
 A database is a collection of individual
observations without summarizing
analysis

5. Strategies of Medical Data
Selection and Use
 All medical databases are basically
incomplete because they reflect the
selective collection of data by the
health care personnel
 The challenge is to ask only questions
that are necessary, to perform only the
examinations that are required and to
record only pertinent data

6. The Hypothetico - Deductive
Approach
 Studies of medical decision makers have
shown that strategies for data collection
and interpretation may be imbedded in
an interative process known as
hypothetico-deductive approach
 The central idea is one of
seuqential, staged data
collection, followed by data interpretation
and the generation of
hypotheses, leading to hipothesis-
directed selection of the next most
appropiate data to be collected.

7. The Hypothetico - Deductive
Approach
 Physicians refers to the set of active
hypothesis as the differential
diagnosis
 Physicians have developed safety
measures to avoid missing important
issues. They are focused in four
categories:
◦ Past medical history
◦ Family history
◦ Social history
◦ Review of systems

8. The Hypothetico - Deductive
Approach
 After finishing with the physical
examination the list of hipotheses may
be narrowed down sufficiently that the
physician can undertake specific
treatment
 It often is necessary to gather aditional
data
 The response of the patient to
treatment is itself a datum point that
may affect the hypotheses about a
patient’s illness

9. The relationship between data
and hypotheses
 Observation evokes a hypothesis
 Sensitivity: the likehood that a given
datum will be observed in a patient
with a given disease or condition
 Specificity. An observation is highly
specific for a disease if it is generally
not seen in patients who do not have
that disease

10. The relationship between data
and hypotheses
 The prevalence of a disease is simply
a measure of the frequency with which
the disease occurs in the population of
interest
 The predictive value of a test is simply
the post-test probability that a disease
is present based on the results of a
test

11. Methods for selecting questions
and comparing tests
 Given a set of current
hypotheses, how does the physician
decide what additional data should be
collected?

12. The Computer and Collection of
Medical Data
 The need for data entry by physicians
has posed a problem for medical
computing systems since the earliest
days of the field
 In some applications is possible for
data to be enterred automatically into
the computer
 The use of touch-
screens, mouse, PDA’s can help to
reduce the resistance to computer use