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introduction to the design of diagnostic criteria. Joop P van de Merwe Dept. of Immunology & Internal Medicine Erasmus MC Rotterdam [email protected] ESSIC Meeting Baden 16-18 June 2005. * Fries JF et al . Arthritis Rheum 1994;37:454-62. All Persons. Persons with Diseases.

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Introduction to the design of diagnostic criteria l.jpg

introduction to the design of diagnostic criteria

Joop P van de MerweDept. of Immunology & Internal MedicineErasmus MC [email protected] Meeting Baden 16-18 June 2005


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* Fries JF et al. Arthritis Rheum 1994;37:454-62


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All Persons

Persons with Diseases

Persons with Confusable

Diseases

Persons

with Target

Disease

CLASSIFICATION CRITERIA*

Classification criteria separate patients with the disease from the general population and from patients with potentially confusable conditions

* Fries JF et al. Arthritis Rheum 1994;37:454-62 (modified)


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the problem

overlapping features

example: systemic autoimmune diseases


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systemic autoimmune diseases (1)

examples

  • rheumatoïd arthritis

  • Sjögren's syndrome

  • systemic lupus erythematosus (SLE)

  • antiphospholipid syndrome (APS)

  • mixed connective tissue disease (MCTD)

  • systemic sclerosis (scleroderma, CREST-syndrome)

  • polymyositis / dermatomyositis

  • relapsing polychondritis


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systemic autoimmune diseases (2)

possible features

  • clinical

  • arthritis / arthralgia

  • vasculitis

  • fever

  • Raynaud's phenomenon

  • fatigue

  • various renal diseases

  • laboratory

  • increased ESR, CRP

  • anaemia

  • leukopenia

  • rheumatoid factor

  • ANA

  • trombopenia

not specific for

one single disease

not specific for

one single disease


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systemic autoimmune diseases (3)

possible accompaning organspecific autoimmune diseases

  • atrophic gastritis - pernicious anaemia

  • Hashimoto's disease

  • keratoconjunctivitis sicca

  • lymfocytic interstitial pneumonitis

  • myositis

  • pericarditis, pleuritis

  • peripheral neuropathy

  • uveitis (iritis, iridocyclitis)

  • scleritis

  • interstitial cystitis

no combination is specific

for one single disease


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systemic autoimmune diseases (4)

how do you recognize them ?


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people

how do you recognize them ?

each person

has a face


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people

how do you recognize them ?

none of the

parts of the

face is unique,

but the

combination is


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people

how do you recognize them ?

none of the

parts of the

code is unique,

but the

combination is


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systemic autoimmune diseases (4)

how do you recognize them ?

each autoimmune disease

has its own "face"


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systemic autoimmune diseases (5)

characteristic features

characteristic feature

specific way it affects the lacrimal

and salivary glands

specific way it affects the joints

specific way it affects the skin

specific way it affects the skin

combination of clinical symptoms

and anti-RNP

specific way it affects the skin

combination of symptoms

disease

Sjögren's syndrome

rheumatoid arthritis

systemic lupus erythematosus

subacute cutaneous lupus

erythematosus

mixed connective tissue disease

(MCTD)

systemic sclerosis (scleroderma)

CREST syndrome


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characteristic features

what are the characteristic features of IC ?

  • what is the consequence of the PBS/IC concept ?

ICS definition of PBS/IC

PBS: "suprapubic pain related to bladder filling,

accompanied by other symptoms such as increased

daytime and nighttime frequency in the absence of

infection or other pathology"

IC: above with "typical cystoscopic and histological features"


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characteristic features

what are the characteristic features of IC ?

ICS definition of IC may be written as:

suprapubic pain related to bladder filling,

accompanied by other symptoms such as increased

daytime and nighttime frequency with typical cystoscopic

and histological featuresin the absence of

infection or other pathology

what are the "typical cystoscopic and histological featuresof IC" ?

what has happened to urgency ?


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characteristic features

what are the "typical cystoscopic and histological featuresof IC" ?

  • Cysto features: Hunner's ulcer or low capacity

  • epithelial denudation, submucosal inflammation,

    granulation tissue, edema, congestion,

  • haemorrhage; detrusor fibrosis (and myopathy)

  • increased mast cell number & activation and

    neuronal staining

from: Hanno P, Burks D. Painful bladder syndrome / interstitial

cystitis. Course 93 IC, AUA 2005 Annual Meeting, San Antonio,

TX, May 21-26,2005


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characteristic features

  • Cysto features: Hunner's ulcer or low capacity

  • epithelial denudation, submucosal inflammation,

    granulation tissue, edema, congestion,

  • haemorrhage; detrusor fibrosis (and myopathy)

  • increased mast cell number & activation and

    neuronal staining

but these are not

unique for IC !

from: Hanno P, Burks D. Painful bladder syndrome / interstitial

cystitis. Course 93 IC, AUA 2005 Annual Meeting, San Antonio,

TX, May 21-26,2005

does this matter as long as the combination is unique ?


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PBS

or

IC

IC

IC has "typical" cystoscopic and histological featuresof IC in addition to

suprapubic pain and frequency

PBS / IC concept

PBS


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gold standard

gold standard = diagnosis by experts

why ?

- the diagnosis by experts is the best standard we have

as long as the cause of a disease is unknown

advantage

- non-experts can diagnose a disease as if they were

experts (skill level)

- diagnoses are made on the same basis by experts

and non-experts (uniformity)

- rules are based on information from many experts

(acceptance and support)


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classification methods (1)

classification tree

the classification tree is

constructed by repeated

splits of groups into

2 descendant subgroups

Arthritis Rheum 1990;33:1137-44


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classification tree

  • pro

  • items may be polychotomous or continuous

  • nonparametric: no reference to a model for the

  • relationship between classification items and disease

  • status

  • high information content - classified groups of subjects in

  • studies may be referred to the exact classifying subgroup

  • of the tree

Arthritis Rheum 1990;33:1137-44


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"number of criteria present rule"

Ann Rheum Dis 2002;61:554-8


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classification methods (2)

"number of items present rule"

  • pro

  • simple definitions (+/-): easy application

  • con

  • simple definitions (+/-):

  • - all items are given equal weight

  • - all items must be dichotomous (+/-)

  •  little insight into the characteristics of a

  • classified patient group

Arthritis Rheum 1990;33:1137-44


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suggested approach in a multicentre study

1. collect what information (symptoms and signs*) is used

by experts to diagnose IC and

differentiate IC from confusable diseases

for both men and women

* requires definitions and decisions on data format


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suggested approach in a multicentre study

2. collection of data from

patients with IC and

patients with confusable diseases

to define classification criteria for IC

(training phase)

sensitivity

specificity

calculate an optimal combination

on the basis of how many

false negative and false positive

diagnoses we accept


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suggested approach in a multicentre study

3.validation with new patient groups

the same database can be used to create

number of items present rule

for clinical diagnoses and a

classification tree

for scientific studies


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data format

data may be

- continuous

avoid entry of cut-off points for continuous data

but have the statistical analysis decide

- categorical


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to be evaluated ….

tests to be evaluated for their diagnostic value

should be done in all patients with IC and confusable

diseases

1. antiproliferative factor

2. ................................

3. ................................


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summary & conclusions (1)

1. decision on broad definition of IC

PBS + "typical" cystoscopy and/or histology

2. select diseases with which IC can be confused

(confusable diseases, CD)

list to be discussed this morning

3. what information is needed to distinguish IC from CD:

follows from (2) but needs discussion and decision

4.decision onwhat percentage of false negative and

false positive diagnoses we accept


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summary & conclusions (2)

5. decision on gold standard for the diagnosis IC

diagnosis by experts

6. decision on methods of classification

classification tree and

"number of items present rule"

7.decision to perform a small pilot to test procedures

8.decision on tests to be evaluated

APF test


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consensus on IC


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