27 Nov 2009 Dar es Salaam 1 David Coulter
27 Nov 2009Dar es Salaam 1
David Coulter
Summary of content
What is a signal? Recognising a signal What can be achieved by you? Clinical assessment of individual
events Clinical review of collated events Principles of signal detection Ta
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Definition 1
A signal refers to ‘reported information on a possible causal relationship between an adverse event and a drug, the relationship being unknown or incompletely documented previously’.
WHO
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Definition 2
In practice it means, a strong suspicion of an adverse reaction that has not been recognised previously
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Recognising a signal
Signal identification
Record
Collate
Look!!
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Recognition of a signal 1
How do we know when events are not recognised reactions?
Martindale* DrugDex* Physicians Desk Reference (PDR).
All available on website of Micromedex Healthcare Series www.thomsonhc.com
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Recognition of a signal 2 You don’t need to do data mining
(BCPNN), or proportional reporting ratios (PRR), or disproportionality analysis to identify signals
Careful clinical assessment of your own events data is the quickest and most satisfying way.
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Recognition of a signal 3
Routine clinical appraisal facilitates the earliest possible generation of hypotheses
Automated signal detection good for testing hypotheses identifying missed signals still needs clinical confirmation
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Recognition of a signal 4
Clinical review the quickest method
careful informed systematic standardised clinical review In your centre
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What can be achieved –by you?
What can be achieved?
Example: IMMP -omeprazole Hyponatraemia Dry mouth Taste disturbance Interstitial nephritis Polydypsia / polyuria Polymyositis
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Omeprazole
Hepatitis Angioedema / urticaria Bone marrow depression Carcinoid tumour Gastric polyps Diarrhoea
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Omeprazole
Hallucinations Amnesia / confusion Headache Myalgia Gynaecomastia / galactorrhoea
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Omeprazole
Paraesthesia Pruritus Rash Extrapyramidal symptoms Blood dyscrasias
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Clinical assessment of individual events
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COX-2 inhibitors and disturbance of vision
Example 1
M 78 Shoulder pain Rofecoxib 50 mg once Woke next morning with
no vision right eye 6/18 left eye
Recovered next day
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Example 1
M 81 Osteoarthritis knee Celecoxib 100mg daily Central loss of vision Onset after each morning dose,
recovering after a few hours No recurrence after withdrawal
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Example 1
These 2 case reports can be called the INDEX CASES
Contain good information close time relationship positive dechallenge one had rechallenge
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Example 1
Now we look for information that may strengthen the signal:
Other case reports WHO database (Vigibase) Literature Mechanism
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Example 1Other reports of eye problems -blurred vision
Patient Dose Onset
Rof M 58 ? 1 week
Cel F 53 200mg 4 months
Cel F 59 200mg 1 week
Cel F71 200 ?
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Example 1WHO reports
Celecoxib Blindness 12 Temporary blindness 4 Vision abnormal 181
Rofecoxib Blindness 22 Temporary blindness 5 Vision abnormal 167
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Example 1Literature search
One case report with celecoxib Orange spots in both visual fields. (Lund
& Neiman, 2001) No reports with rofecoxib Visual field defects have been
reported rarely with the traditional NSAIDs
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Example 1Mechanism
Interference with retinal blood flow by inhibition of prostaglandins and related substances.
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Example 1Conclusion
Two good index cases Several supporting cases Supporting cases in WHO database Similar reports for related drugs A plausible mechanism Only one similar report in the
literature We have a signal!
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Clinical review of collated events
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COX-2 inhibitors and prothrombotic disorders
Demo
Cluster of events
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Profile of Incidents - Celecoxib and Rofecoxib n=131 n=71
00
64
23
56
1
54
332
4
51
1
4
934
7
00
21
8
0000
1
3
5
29
8
5
0
5
10
15
20
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35
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45
Accid
ents
Alimen
tary
Autonom
ic
Circula
tory
Endocrin
e/M
etab
olic ENTEye
s
Haem
atolo
gical
Hepat
obili
ary
Imm
unolo
gical
Infe
ctio
ns
Musc
ulosk
elet
al
Neopla
sms
Neuro
logi
cal
Psych
iatri
c
Respira
tory
Skin
Urogen
ital
System Organ Class
% o
f T
ota
l In
cid
ents
Celecoxib
Rofecoxib
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Prothrombotic events
Summary of findings No difference in rates of IHD / stroke
between rofecoxib & celecoxib Higher rate of prothrombotic events
than comparators Shorter time to onset of death than
comparators Differences in death rates due to
prothrombotis events Higher rate of cardiac dysrythmias
with celecoxib
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Principles of signal detection
Remember
Treatment dates -starting date & ending
Date of onset of event Was the patient on the drug when
the event began? Calculate onset time Effect of dechallenge / rechallenge
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Signal assessment
Other questions Could the problems be caused by a
disease? The disease being treated A co-morbid condition
Could the problems be caused by another drug?
Are the events caused by related drugs?
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Look for non-random features Gender Age Duration to onset
Survival / life table analysis
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Non-random features
Differences in means Patients with reaction v patients in cohort t-test
Differences in rates RR with CI
Survival or life table analysis Clustering around a certain duration Differences between medicines
Multiple logistic regression
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Collate reports clinically
By Clinical Category (CC) Then in clinically related groups
Anatomical functional change Clinical sub-group
Primary event term Secondary event term
Motto:
Sort & see & pursue27 Nov 2009Dar es Salaam 40
Identifying early signals
Report your signals to: your advisory committee &/or
regulatory authority local health practitioners the Uppsala Monitoring Centre local ADR bulletin medical journal
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Signal identification
Record
Collate
Look!!
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Thank You
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Merci
beaucoup