Drug Hypersensitivity Prevalence in the Adult

Population

Group 13

Faculty of Medicine of the University of PortoFaculty of Medicine of the University of Porto

Department of Biostatistics and Medical InformaticsDepartment of Biostatistics and Medical Informatics2005/062005/06

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Table of contents

Introduction– Aim

Participants and Methods Results Discussion and Limitations Website project

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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. Clin Exp Allergy 2004; 34:1597-1601

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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 R. Drug metabolism, danger signals, and drug-induced hypersensitivity. J Allergy Clin Immunol October 2001

3 –Gruchalla R. Understanding drug allergies. J Allergy Clin Immunol June 2000

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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. Allergy 1999, 54, 999-1003

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Introduction

3-7% of the population experience an adverse drug reaction1

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

1 - Gomes et al. Self-reported drug allergy in a general adult Portuguese population. Clin Exp Allergy 2004; 34:1597-1601

2 - Gruchalla R. Drug metabolism, danger signals, and drug-induced hypersensitivity. J Allergy Clin Immunol October 2001

3 - Gruchalla R. Understanding drug allergies. J Allergy Clin Immunol June 2000

7

Introduction

Drugs most commonly observed as the cause of these reactions3: – ampicillin– amoxicillin– trimethoprim-sulfamethoxazole – penicillin

3 - Gruchalla R. Understanding drug allergies. J Allergy Clin Immunol June 2000

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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. Allergy 1999, 54, 999-1003

© Dermatology database of Institute for Biomedical Informatics, Faculty of Medicine, Ljubljana, Slovenia

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Aim

To determine the lifetime prevalence of drug hypersensitivity in the adult population

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Secondary Aims

Identify the drugs that are more frequently associated to hypersensitive reactions, (classifying them using the same system of INFARMED data base);

Describe the different types of allergic expression;

Relate the allergic reactions already described with the presence of some diseases;

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Study participants Target population - all adult people (above 18

years old) living in Porto region Available population - all adult people living in

Porto region with telephone in their household Unit of Analysis – single person Inclusion Criteria – be an adult, have phone in their

household, live in Porto and have capacities to answer the questionnaire properly

Exclusion Criteria – see flowchart

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Flowchart

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Study design

Observational, cross-sectional and descriptive study, executed via phone interviews.

Data collection method – Phone interviews, filling up a questionnaire previously designed

Sample selection method – two stages random digit dialling

Frequency measurement – lifetime prevalence

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Random Digit Dialling5

Two Stages RDD Sampling Methods Will be used relative to the telephone

numbers of Porto region. Software will randomly select digits of the

type 22xxxxx and generate prefix numbers Software will randomly select two digits and

generate suffix numbers

5 - Groves, R et al. Telephone Survey Methodology. John Wiley & Sons Inc 2001

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Random Digit Dialling

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Data collection methods

Telephone interview Questionnaire

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Main variables description Presence of drug allergies in a life time

period Reaction type (skin, respiratory, digestive,

others) Suspected drug Presence of allergic diseases Other diseases Age Sex

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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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ResultsResults of the phone calls made until 10th March 06

7%5%

50%

23%

15%

Household - answered questionnaire

Household - refused to answer

Not a Household - not available

Not a Household - commercial

Not a Household - others

Total number of calls: 649

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Results

Characterization of the people that answered the questionnaire

0

1

2

3

4

5

6

7

18-27 28-37 38-47 48-57 58-67 68-77 78-87 88-97

women

men

Total = 39Mean = 53,41Median = 53,5Missing values = 6

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Expected Results

We expect that our study reveals about 3-7% 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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Results

In your life, have you had problems or felt sick after taking a drug?

80%

20%

YesNo

Total: 45

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Results

In your life, have you had problems or felt sick after taking a drug?

13%

7%

76%

4%

Had problems but notconfirmed by a doctor

had allergy - confirmed bya doctor

No problems and noallergy confirmed

Had allergy confirmed by adoctor but never hadproblems

Total: 45

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3

34

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ResultsFrequency of the allergy symptoms

0

1

2

3

4

5

6

7

8

skin respiratory others digestive

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ResultsDrugs that gave rise to problems

0

1

2

3

4

5

missed data NSAID antibiotic

penicillin

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ResultsAllergies to drugs by age group

0%

5%

10%

15%

20%

25%

30%

18 to 40 41 to 60 more than 60

had problems

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Results

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Main limitations

Telephone interviews may not be accurate enough to determine whether a reaction is really of hypersensitivity or not

People living in Porto, without a telephone at home are excluded

Interviews were done in a restricted period of time

Very low response rate

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Discussion - difficulties Questionnaire introduction was not very

appropriate:– excessive extension;– complexity of phrasal structure and lexicon;

Low cooperation of the inquired population:– difficulties to understand what was being said (advanced

age);– lack of time (active class);

Slanting of the inquired population due to the impossibility of making phone calls during all day:– majority of the population inquired was of advanced age;– phone calls made only in the morning and afternoon;– active population excluded;

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Discussion - difficulties Difficulties to contact the resident:

– the person who answered the phone didn’t live there and was incapable to give us an hour for future contacting;

– Most of the times, the person who was next to celebrate birthday was impossible to reach;

Lots of unfruitful phone calls:– most of the numbers dialed were not available;– great part of the available phone numbers were not residences;– this lead to a waste of precious time;

When the first combination of prefix and suffix was a residence, the majority of next ones weren’t either:– we had to make dozens of phone calls with the same prefix to

obtain five residences.

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Gantt chart

Microsoft Project

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Website projectHome

Abstract

Introduction

Participants and Methods

Results

Discussion

Conclusions

References

Authors and contacts

Full article (pdf)

Work package

Gantt chart

Presentations

SPSS sintax

Related websites

SPSS tables

Abstract in portuguese

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References1 - Gomes et al. Self-reported drug allergy in a general adult

Portuguese population. Clin Exp Allergy 2004; 34:1597-1601

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

The End