Transcript Drug Hypersensibility Prevalence in the Adult Population of Porto

Medical Faculty of University of Porto
Introduction to Medicine
2005/06
Drug Hypersensitivity
Prevalence in the Adult
Population
Group 13
Summary
Introduction
 Aim
 Methods
 Expected Results
 Limitations

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Introduction

Drug hypersensitivity reactions are the side
effects of drugs taken at a dose that is
tolerated by normal subjects1

Drug hypersensitivity reactions are thought
to represent one-third of adverse drug
reactions1
1- Gomes et al. Self-reported drug allergy in a general adult Portuguese population.
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Introduction
80% of adverse drug reactions are
predictable (type A reactions)2
 Type B reactions are not predictable, are
dose independent, are not related with the
pharmacologic actions of the drug and are
extremely important because they are often
serious and can cause death2,3
 Allergic reactions are one of the examples of
unpredictable reactions3

2 - Gruchalla, Rebecca. Drug metabolism, danger signals, and drug-induced hypersensitivity.
3 –Gruchalla, Rebecca. Understanding drug allergies.
4
Introduction
Drug hypersensitivity is a common and
complicated problem in clinical practice4
 It shows in various forms of autoimmune
diseases4
 Diagnosis of drug hypersensibility is difficult4
 Drug-allergic reactions are underdiagnosed4

4– Demoly, P, Kropf, R:, Bircher A. et Pichler W.J. Drug hypersensitivity: questionnaire.
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Introduction
5% of all hospital admissions are due to
adverse drug reactions2
 Fatal adverse drug reactions are between
the 4th and 6th leading cause of death of
hospitalized patients in the USA3
 3-7% of the population experience an
adverse drug reaction1

1- Gomes et al. Self-reported drug allergy in a general adult Portuguese population.
2 - Gruchalla, Rebecca. Drug metabolism, danger signals, and drug-induced hypersensitivity.
3 - Gruchalla, Rebecca. Understanding drug allergies.
6
Introduction

Drugs most commonly observed as the
cause of these reactions3:
– ampicillin
– amoxicillin
– trimethoprim-sulfamethoxazole
– penicillin
3 - Gruchalla, Rebecca. Understanding drug allergies.
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Introduction

Common diseases and symptoms provoked
by drug hypersensitivity4:
– Exanthema (most common)
– Urticaria
– Anaphylaxis
– Blood cell dyscrasia
– Fever
– Intersticial lung disease
– Hepatitis
– Nephritis
4– Demoly, P, Kropf, R:, Bircher A. et Pichler W.J. Drug hypersensitivity: questionnaire.
© Dermatology database of
Institute for Biomedical
Informatics, Faculty of
Medicine, Ljubljana, Slovenia
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Aim
The aim of this study is to determine the
prevalence of drug hypersensitivity in the
adult population of Porto region
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Secondary Aims




Identify the drugs that are more frequently
associated to hypersensitive reactions, classifying
them using the INFARMED data base;
Describe the different types of allergic expression;
Relate the allergic reactions already described with
the presence of some diseases;
Study the possible existence of an association
between drug hypersensitivity in the interviewed
subject and the number of relatives with the same
pathology.
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Study participants





Target population - all adult people (above 18
years old) living in Porto region
Available population - all adult people (above 18
years old) living in Porto region with telephone in
their household
Unit of Analysis – single person
Inclusion Criteria – be an adult (above 18 years
old), have phone in their household, live in Porto
and have capacities to answer the questionnaire
properly
Exclusion Criteria – see fluxogram
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Fluxogram
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Study design
Observational, cross-sectional and
descriptive study, realized by phone
interviews
 Data collection method – Phone interview,
filling up a questionnaire previously designed
 Sample selection method – random digit
dialling
 Frequency measurement - prevalence

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Random Digital Dialling5
Will be aplicated to the telephone numbers
of Porto region
 Software will randomly select digits of the
type 22xxxxxxx, where x is a digit between 0
and 9

5- Groves, R et al. Telephone Survey Methodology.
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Data collection methods
Telephone interview
 Questionnaire

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Main variables description
Age
 Sex
 Reaction type
 Symptoms
 Suspected drug
 Allergies in family medical history

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Statistical Analysis
We will use SPSS® 13.0 software
 Descriptive statistics and hypothesis t tests
shall be used to analyse data
 We will use odds ratio as an association
measure

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Gantt chart

Microsoft Project
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Expected Results

We expect that our study reveals about 37% of adverse drug reactions in our
population as reported1
1- Gomes et al. Self-reported drug allergy in a general adult Portuguese population.
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Main limitations
Telephone interviews are not accurate to
determine whether a reaction is really of
hypersensitivity or not
 People living in Porto, without telephone at
home are excluded
 Interviews will be done in a restricted period
of time
 Low response rate

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References
1 - Gomes et al. Self-reported drug allergy in a general adult
Portuguese population. Clin Exp Allergy 2004; 34:15971601
2 - Gruchalla, Rebecca. Drug metabolism, danger signals, and
drug-induced hypersensitivity. J Allergy Clin Immunol
October 2001
3 - Gruchalla, Rebecca. Understanding drug allergies. J
Allergy Clin Immunol June 2000
4 - Demoly, P, Kropf, R:, Bircher A. et Pichler W.J. Drug
hypersensitivity: questionnaire. Allergy 1999, 54, 999-1003
5 - Groves, R et al. Telephone Survey Methodology. John
Wiley & Sons Inc 2001
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The End