Abstract
Background: Few Randomized Controlled Trials (RCTs) have evaluated oral
immunotherapy effects on quality of life (QoL). We previously reported
that probiotic peanut oral immunotherapy (PPOIT) significantly improved
QoL compared with placebo, with improvement linked to achieving
sustained unresponsiveness (SU). Objective: We examined whether
PPOIT-induced QoL improvement is maintained at 4 years post-treatment.
Methods: Subjects in the PPOIT-001 RCT (n=57) completed Food Allergy
Quality of Life Questionnaire-Parent Form (FAQLQ-PF) and Food Allergy
Independent Measure (FAIM) at pre-treatment, end-of-treatment, and
3-months, 12-months and 4-years post-treatment. Paired group t-test
analyses were conducted separately for PPOIT and Placebo groups at each
time point. Repeated-measures mixed ANOVAs were used to examine overall
changes from pre-treatment to 4-years post-treatment, controlling for
potential confounders. Results: N=38 (19 Placebo/19 PPOIT) completed
FAQLQ at ALL time-points. PPOIT-treated subjects had significantly
improved FAQLQ compared with placebo at 3-months, 12-months and 4-years
post-treatment. FAQLQ and FAIM scores improved significantly for PPOIT
group from pre-treatment to 4-years post-treatment (both p=0.001).
Multivariate analysis (controlling for age, sex, SU) confirmed findings,
with a very large effect size [partial eta squared=0.56]. A ‘large’
amount of peanut ingestion predicted greater improvement in FAQLQ score,
compared with avoidance, small or moderate ingestion. No changes from
baseline in FAQLQ or FAIM were shown for placebo. Conclusions: PPOIT
induced substantial improvement in FAQLQ that persisted to 4-years
post-treatment. Greatest benefit was observed in subjects ingesting
large amounts of peanut. This is the first study demonstrating
long-lasting improvement in QoL with a food allergy treatment.