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Validation of epidemiological tools for eczema diagnosis in Brazilian children: the ISAAC's and UK Working Party's criteria.

Strina A, Barreto ML, Cunha S, de Fátima S P de Oliveira M, Moreira SC, Williams HC, Rodrigues LC - BMC Dermatol. (2010)

Bottom Line: A limitation is that questionnaire was already validated in Brazil, but not field tested in this specific setting.Studies using UKWP or ISAAC criteria should include a validation arm, to contribute to the understanding of potential limitations of their use in different contexts and to explore solutions.We list specific recommendations.

View Article: PubMed Central - HTML - PubMed

Affiliation: Universidade Federal da Bahia, Instituto de Saúde Coletiva, Salvador, Brazil. agstrina@yahoo.com.br

ABSTRACT

Background: Instruments for field diagnosis of eczema are increasingly used, and it is essential to understand specific limitations to make best use of their strengths. Our objective was to assess the validity of ISAAC and UK Working Party criteria for field diagnosis of eczema in children.

Methods: We performed a cohort study in urban Brazil. Parents/guardians of 1,419 children answered ISAAC phase II questionnaire. Children were examined for skin lesions (UKWP protocol). Two dermatologists examined most cases of eczema (according to ISAAC or UKWP), and a sample without eczema.

Results: Agreement between repeat questionnaires on the filter question was poor (kappa = 0.4). Agreement between the 2 dermatologists was fair (kappa = 0.6). False positive reports included scabies in 39% of ISAAC cases and 33% of UKWP cases. Sensitivity and PPV were low (ISAAC: 37.1% and 16.1%; UKWP: 28.6% and 23.8%). Specificity and NPV were high (ISAAC: 90.0% and 96.6%; UKWP: 95.3% and 96.2%). One-year prevalence of eczema was 11.3% (ISAAC), 5.9% (UKWP) and 4.9% (adjusted dermatologist diagnosis). Point prevalence of scabies (alone or not) was 43%, 33% and 18%, in eczemas according to ISAAC, to UKWP and to dermatologists. The reasons why children with eczema were not identified by ISAAC or UKWP were wrongly denying dry skin, itchy rash or personal history of atopic diseases. A limitation is that questionnaire was already validated in Brazil, but not field tested in this specific setting.

Conclusions: Studies using UKWP or ISAAC criteria should include a validation arm, to contribute to the understanding of potential limitations of their use in different contexts and to explore solutions. We list specific recommendations.

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Field Questionnaire.
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Figure 1: Field Questionnaire.

Mentions: The study population consisted of 1,419 children. Their parent\guardians answered the ISAAC phase II core questionnaire for eczema [24], translated into Portuguese and back-translated into English, and validated [18]. The relevant questions are presented in Figure 1. The children were also examined for skin lesions according to the UKWP protocol. Because of the overlap between slightly different filter questions in ISAAC and UKWP questionnaires, we used only the ISAAC version so that the first two questions of the ISAAC core questionnaire ("Has your child ever had an itchy rash that came and went for at least 6 months?" and "Has your child had this itchy rash at any time in the last 12 months?") were used as filter questions for the UKWP protocol too, in place of the original one ("Has your child had an itchy skin condition in the last 12 months?"). So we departed from the recommended UKWP protocol only in that we included in the screening questions a requirement for the itchy lesion to come and go for at least 6 months rather than just having been present.


Validation of epidemiological tools for eczema diagnosis in Brazilian children: the ISAAC's and UK Working Party's criteria.

Strina A, Barreto ML, Cunha S, de Fátima S P de Oliveira M, Moreira SC, Williams HC, Rodrigues LC - BMC Dermatol. (2010)

Field Questionnaire.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2992474&req=5

Figure 1: Field Questionnaire.
Mentions: The study population consisted of 1,419 children. Their parent\guardians answered the ISAAC phase II core questionnaire for eczema [24], translated into Portuguese and back-translated into English, and validated [18]. The relevant questions are presented in Figure 1. The children were also examined for skin lesions according to the UKWP protocol. Because of the overlap between slightly different filter questions in ISAAC and UKWP questionnaires, we used only the ISAAC version so that the first two questions of the ISAAC core questionnaire ("Has your child ever had an itchy rash that came and went for at least 6 months?" and "Has your child had this itchy rash at any time in the last 12 months?") were used as filter questions for the UKWP protocol too, in place of the original one ("Has your child had an itchy skin condition in the last 12 months?"). So we departed from the recommended UKWP protocol only in that we included in the screening questions a requirement for the itchy lesion to come and go for at least 6 months rather than just having been present.

Bottom Line: A limitation is that questionnaire was already validated in Brazil, but not field tested in this specific setting.Studies using UKWP or ISAAC criteria should include a validation arm, to contribute to the understanding of potential limitations of their use in different contexts and to explore solutions.We list specific recommendations.

View Article: PubMed Central - HTML - PubMed

Affiliation: Universidade Federal da Bahia, Instituto de Saúde Coletiva, Salvador, Brazil. agstrina@yahoo.com.br

ABSTRACT

Background: Instruments for field diagnosis of eczema are increasingly used, and it is essential to understand specific limitations to make best use of their strengths. Our objective was to assess the validity of ISAAC and UK Working Party criteria for field diagnosis of eczema in children.

Methods: We performed a cohort study in urban Brazil. Parents/guardians of 1,419 children answered ISAAC phase II questionnaire. Children were examined for skin lesions (UKWP protocol). Two dermatologists examined most cases of eczema (according to ISAAC or UKWP), and a sample without eczema.

Results: Agreement between repeat questionnaires on the filter question was poor (kappa = 0.4). Agreement between the 2 dermatologists was fair (kappa = 0.6). False positive reports included scabies in 39% of ISAAC cases and 33% of UKWP cases. Sensitivity and PPV were low (ISAAC: 37.1% and 16.1%; UKWP: 28.6% and 23.8%). Specificity and NPV were high (ISAAC: 90.0% and 96.6%; UKWP: 95.3% and 96.2%). One-year prevalence of eczema was 11.3% (ISAAC), 5.9% (UKWP) and 4.9% (adjusted dermatologist diagnosis). Point prevalence of scabies (alone or not) was 43%, 33% and 18%, in eczemas according to ISAAC, to UKWP and to dermatologists. The reasons why children with eczema were not identified by ISAAC or UKWP were wrongly denying dry skin, itchy rash or personal history of atopic diseases. A limitation is that questionnaire was already validated in Brazil, but not field tested in this specific setting.

Conclusions: Studies using UKWP or ISAAC criteria should include a validation arm, to contribute to the understanding of potential limitations of their use in different contexts and to explore solutions. We list specific recommendations.

Show MeSH
Related in: MedlinePlus