In contrast, in the subgroups of infants with family histories of asthma or atopy/food allergies, the differences in time to third episode between the treated and untreated groups were not statistically significant. physician-diagnosed recurrent wheezing through the ages of 2 to 5 years was 68% in those with no family history of asthma (odds ratio, 0.32; (95% CI, 0.14-0.75; N?= 146 palivizumab-treated, 171 untreated) and 80% in those with no family history of atopy or food allergies (odds ratio, 0.20; 95% CI, 0.07-0.59; N?= 101 palivizumab-treated, 100 untreated). In contrast, there was no effect of palivizumab on subsequent recurrent wheezing in the 90 children with a family history of atopy or food allergies compared to 130 untreated infants with atopic families. Conclusion Respiratory syncytial virus prophylaxis in nonatopic children decreases by 80% the relative risk of recurrent wheezing but does not have any effect in infants with an atopic family history. This suggests that RSV predisposes to recurrent wheezing in an atopy-independent mechanism. subgroups of infants were determined on the basis of whether the following were present at baseline: family history of asthma and Trimethadione family history LAG3 of atopy (asthma, atopic dermatitis, or allergic rhinitis) or food allergies. Family was defined as anyone in the immediate family. Analyses were performed within these subgroups. A?sample size of 200 infants per group would provide approximately 80% power for a 2-sided, .05-level test to detect as statistically significant a difference in physician-diagnosed recurrent wheezing rates when the true rates were 3% for the prophylaxed group and 10% for the untreated controls. This study was not powered to test for differences within the subgroups previously specified. Demographics and baseline characteristics were analyzed for quantitative variables by using 1-way ANOVA and for categorical variables by using the Fisher exact test. Comparisons between the treated and untreated groups in incidence of physician-diagnosed recurrent wheezing were performed by using the Trimethadione Fisher exact test; the relative risk (RR) and 95% CI for the RR were calculated. The potential influence of baseline characteristics was explored with multiple logistic regression with covariates for RSV hospitalization history, sex, age at enrollment, gestational age at birth, birth weight, multiple birth status, baseline RSV-neutralizing antibody titers (log2 RSV antibody Trimethadione level), day care attendance, numbers of adults and siblings in the home, number of siblings in day care, presence of a wood-burning stove in the home, and family history of asthma, atopic dermatitis, allergic rhinitis, or food allergies. Time to third physician-diagnosed wheezing episode was analyzed with multivariable Cox proportional hazards models including the covariates listed. For each logistic regression and Cox proportional hazards analysis, a forward stepwise selection method was used to determine factors significant at the .15 level; these factors were included in the final model. Only factors significant at the .05 level in the final model were displayed. Comparisons between the treated and untreated groups in time to third physician-diagnosed wheezing episode were performed Trimethadione by using the log-rank test, and Kaplan-Meier estimates were computed and displayed graphically. Results There were 191 children in the palivizumab-treated group and 230 in the untreated group, among whom 154 were not hospitalized with RSV and 76 were hospitalized with Trimethadione RSV. Of the 27 centers that enrolled subjects, 13 had subjects discontinue on or before day 730 (2-year cutoff). Sixteen (8.4%) in the palivizumab-treated group versus 21 (9.1%) in the 230 children not receiving palivizumab were discontinued before day 730. This difference was not statistically significant ( .050. ? .010. ? .001 for comparison with palivizumab-treated group. The 75 children were a subgroup of the 100 untreated subjects. Table II Demographics and baseline characteristicssubjects with family history of atopy (asthma, allergic dermatitis, or allergic rhinitis) or food allergies .050. ? .010. ? .001 for comparison with palivizumab-treated group. The 79 children were a subgroup of the 130 untreated subjects. Significantly smaller proportions of palivizumab-treated children had physician-diagnosed recurrent wheezing during the first 24 months of follow-up compared to the combined untreated groups in the subgroups of children with (1) no family history of asthma (not applicable, variable was not included in the final model. ?Statistically significant at the .050 level. ?Statistically significant at the .010 level. When we examined the time to the third episode of physician-diagnosed wheezing by using Kaplan-Meier methodology (Fig?2 ), the palivizumab-treated group demonstrated significantly longer times to the third episode in subgroups of infants with no family history of asthma or atopy/food allergies. In contrast, in the subgroups of infants with family histories of asthma or atopy/food allergies, the differences in time to third episode between.
