A Long Term, Observational Follow-Up Study of Children and Young People Who Underwent an 18-Month Course of Oral Immunotherapy Treatment for Peanut, Egg or Milk Allergy (5-15 Years Post-Treatment)

HRQL scores were collected via validated surveys (FAQLQ) during the parent studies (PEAT, PrEMO, PPOIT-001 and PPOIT-002), and will be used again in this study for comparison. Changes in HRQL scores from the parent study (baseline) to 5-15 years after stopping OIT will be compared between the clinical outcome groups (Allergic or Sustained Unresponsiveness (SU)/Remission), as determined by the clinical outcome achieved at the end of treatment in the parent study. HRQL scores (reported as mean and standard deviation) will compare changes between the clinical outcome groups using generalised linear modules, adjusted for continuous variables as well as baseline HRQL scores. If continuous outcomes do not follow normal distribution they will be summarised as median and interquartile ranges (IQR), and comparison between the groups will be performed using the Wilcoxon rank-sum (Mann-Whitney) test.

HRQL scores were collected via validated surveys (FAQLQ) during the parent studies (PEAT, PrEMO, PPOIT-001 and PPOIT-002), and will be used again in this study for comparison. Changes in HRQL scores from the parent study (baseline) to 5-15 years after stopping OIT will be compared between the treatment groups (OIT or placebo), as determined by the treatment group allocated in the parent study. HRQL scores (reported as mean and standard deviation) will compare changes between the treatment groups using linear regression adjusted for baseline HRQL scores. If continuous outcomes do not follow normal distribution they will be summarised as median and interquartile ranges (IQR), and comparison between the groups will be performed using the Wilcoxon rank-sum (Mann-Whitney) test.

Participants will complete a REDCap Allergen Specific Questionnaire indicating the number (0, 1, 2, 3, 4, 5, more than 5) of allergic reactions they experienced in the preceding 12 months to the allergen they received OIT treatment for in the parent study (peanut, egg or milk). In this REDCap Allergen Specific Questionnaire, participants will also indicate the number of times an Adrenaline Autoinjector was required for the management of the allergic reaction/s (0, 1, 2, 3, 4, 5, more than 5) in the preceding 12 months. Comparisons (reported as mean and standard deviation) will be made between the clinical outcome groups (Allergic or Sustained Unresponsiveness (SU)/Remission), as determined by the clinical outcome achieved at the end of treatment in the parent study. If continuous outcomes do not follow normal distribution they will be summarised as median and interquartile ranges (IQR), and comparison between the groups will be performed using the Wilcoxon rank-sum (Mann-Whitney) test

Participants will complete a REDCap Allergen Specific Questionnaire indicating the number (0, 1, 2, 3, 4, 5, more than 5) of allergic reactions they experienced in the preceding 12 months to the allergen they received OIT treatment for in the parent study (peanut, egg or milk). In this REDCap Allergen Specific Questionnaire, participants will also indicate the number of times an Adrenaline Autoinjector was required for the management of the allergic reaction/s (0, 1, 2, 3, 4, 5, more than 5) in the preceding 12 months. Comparisons (reported as mean and standard deviation) will be made between the treatment groups (OIT or placebo), as determined by the treatment group allocated in the parent study. If continuous outcomes do not follow normal distribution they will be summarised as median and interquartile ranges (IQR), and comparison between the groups will be performed using the Wilcoxon rank-sum (Mann-Whitney) test.

Participants will complete a REDCap Allergen Specific Questionnaire indicating ingestion in the preceding 12 months (yes/no) of the allergen they received OIT treatment for in the parent study (peanut, egg or milk). Comparisons (reported as absolute and relative frequencies) will be made between the clinical outcome groups (Allergic or Sustained Unresponsiveness (SU)/Remission), as determined by the clinical outcome achieved at the end of treatment in the parent study. Categorical outcomes such as allergen intake (yes/no) will be summarised as the number and proportion of subjects by clinical outcome group.

Allergen specific immunoglobulin E (sIgE) blood levels were collected during the parent studies (PEAT, PrEMO, PPOIT-001 and PPOIT-002) and will be collected again in this study for comparison. Changes (reported as mean and standard deviation) in sIgE blood levels from the parent study (baseline) to 5-15 years after stopping OIT will be compared between the clinical outcome groups (Allergic or Sustained Unresponsiveness (SU)/Remission), as determined by the clinical outcome achieved at the end of treatment in the parent study. If continuous outcomes do not follow normal distribution they will be summarised as median and interquartile ranges (IQR), and comparison between the groups will be performed using the Wilcoxon rank-sum (Mann-Whitney) test.

Allergen specific immunoglobulin E (sIgE) blood levels were collected during the parent studies (PEAT, PrEMO, PPOIT-001 and PPOIT-002) and will be collected again in this study for comparison. Changes (reported as mean and standard deviation) in sIgE blood levels from the parent study (baseline) to 5-15 years after stopping OIT will be compared between the treatment groups (OIT or placebo), as determined by the treatment group allocated in the parent study. If continuous outcomes do not follow normal distribution they will be summarised as median and interquartile ranges (IQR), and comparison between the groups will be performed using the Wilcoxon rank-sum (Mann-Whitney) test.