The challenges of replicating the methodology between Phases I and III of the ISAAC programme

• Published in: The international journal of tuberculosis and lung disease Vol. 16; no. 5; pp. 687 - 693
• Main Authors: Ellwood, P., Asher, M. I., Stewart, A. W., Aït-Khaled, N., Mallol, J., Strachan, D., ISAAC Phase III Time Trends Study Group
• Format: Journal Article
• Language: English
• Published: Paris, France International Union Against Tuberculosis and Lung Disease 01.05.2012; International Union against Tuberculosis and Lung Disease
• Subjects: Adolescent; Adolescents; Age Factors; Asthma - epidemiology; Asthma - pathology; Bacterial diseases; Biological and medical sciences; Child; Children; Cross-Sectional Studies; Eczema - epidemiology; Eczema - pathology; Epidemiologic Methods; Human bacterial diseases; Humans; Infectious diseases; International Cooperation; Isaac; Medical sciences; Methodology; Odds Ratio; Pneumology; Prevalence; Replication; Respiratory system : syndromes and miscellaneous diseases; Rhinitis, Allergic, Perennial - epidemiology; Rhinitis, Allergic, Perennial - pathology; Rhinitis, Allergic, Seasonal - epidemiology; Rhinitis, Allergic, Seasonal - pathology; Tuberculosis and atypical mycobacterial infections; Human; Phase III trial; Methodology; Respiratory disease; adolescents; Mycobacterial infection; Infection; ISAAC; Tuberculosis; children; Adolescent; Bacteriosis; Phase I trial; Replication; Child; Pneumology
• ISSN: 1027-3719; 1815-7920
• DOI: 10.5588/ijtld.11.0226

BACKGROUND: The International Study of Asthma and Allergies in Childhood (ISAAC) used standardised methods to examine symptom prevalence of asthma, rhinitis and eczema in adolescents and children between Phases I and III. Centres followed essential rules to ensure comparability of methodology, examined by a centralised data centre.METHODS: Centre reports (CRs) were compared for both phases and age groups. Methodological differences were categorised under major deviations (centres excluded), minor deviations (deviations identified in published tables) and very minor deviations (deviations not identified).RESULTS: There were 112 CRs for adolescents and 70 for children. Six centres for adolescents and four for children had major deviations and were excluded. Minor deviations (35 for adolescents and 20 for children) were identified in the publications. Very minor deviations (92 for adolescents and 51 for children) were not identified. The odds ratios for having any differences in methodology between phases with a change in Principal Investigator were 0.80 (95%CI 0.36-1.81) for adolescents and 0.91 (95%CI 0.32-2.62) for children.CONCLUSION: The majority of the centres replicated the ISAAC methodology to a high standard. Careful documentation of methodology using standardised tools with careful checks allows the full potential of studies such as ISAAC to be realised.