Abstract
OBJECTIVE: Growing evidence suggests that probiotics may offer therapeutic benefits for asthma, attracting increasing scientific attention. To clarify their effects in pediatric patients with asthma, we conducted a systematic review and meta-analysis using trial sequential analysis (TSA). METHODS: A comprehensive search of five electronic databases was performed for studies published until August 30, 2025. Data on study characteristics, outcomes, and risk of bias were extracted. The meta-analysis was conducted using RevMan 5.3, and TSA was performed using TSA 0.9.5.10 beta. Dichotomous outcomes were expressed as risk ratios, and continuous outcomes as mean difference or standardized mean difference (SMD). Publication bias was assessed using funnel plots and the certainty of the evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation approach. RESULTS: Six randomized controlled trials (RCTs) involving 731 pediatric patients with asthma were included. The pooled analysis indicated that probiotics significantly reduced interleukin-4 (IL-4) levels [SMD -0.66, 95% confidence intervals (CI) -1.24 to -0.08, P = 0.03] and significantly increased those of interferon-γ (INF-γ) (SMD 1.78, 95% CI 0.13-3.44, P = 0.03). However, probiotics did not significantly affect daytime or nighttime asthma symptom scores, forced expiratory volume in 1 s, forced vital capacity, peak expiratory flow, or tumor necrosis factor-α levels (P ≥ 0.05). TSA did not confirm the conclusiveness of the findings for IL-4 and INF-γ, indicating insufficient evidence to support their clinical significance. Additionally, the funnel plots suggested potential publication bias for these outcomes. The certainty of the evidence for all outcomes was rated as very low. CONCLUSION: Although probiotics showed statistically significant effects on IL-4 and INF-γ, the TSA results revealed that neither outcome crossed the monitoring boundaries, indicating that the evidence remains insufficient. Moreover, the very low certainty of the evidence and the fact that all included RCTs were conducted in China suggest that external validity is limited. In view of these uncertainties, the available evidence does not support the routine use of probiotics as an adjunctive therapy in pediatric asthma, and further large-scale, multicenter, RCTs are warranted. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO/view/CRD420251174081, identifier CRD420251174081.