The efficacy and safety of oral microecological agents as add‐on therapy for atopic dermatitis: A systematic review and meta‐analysis of randomized clinical trials

BACKGROUND: Atopic dermatitis (AD) is a common skin disease that is hard to completely cure in a short time. Guidelines recommend the use of topical corticosteroids (TCS) as first‐line anti‐inflammatory therapy for AD, but long‐term use has significant side effects. Microecological agents (MA), including probiotics, prebiotics and synbiotics, have been widely reported as a potential adjunctive therapy of AD, but whether MA can contribute to AD treatment is currently controversial. Therefore, we conducted a systematic review and meta‐analysis to investigate whether MA as an add‐on therapy for AD has synergistic and attenuated effects and to further understand the role of MA in clinical interventions for AD. METHODS: We systematically searched Medline, Embase, Web of Science, Cochrane Library and PsycINFO databases up to Apr 11, 2023, and bibliographies were also manually searched, for potentially relevant studies regarding MA as additional therapy of AD. The Cochrane Risk of Bias Tool for assessing risk of bias was used to assess the quality of randomized controlled trials (RCTs). Two reviewers screened studies, extracted data, and evaluated the risk of bias independently. The primary outcomes (SCORAD scores and the number of adverse events) and the secondary outcomes (pruritus scores, the quality of life and the frequency of TCS) were extracted from each article. The data were combined and analyzed to quantify the safety and efficacy of the treatment. R (V4.4.3) software was used for data synthesis. The certainty of the evidence was evaluated with the Grade of Recommendation, Assessment, Development and Evaluation (GRADE) system. We also performed a trial sequential analysis to assess the reliability of the evidence. RESULTS: A total of 21 studies, including 1230 individuals, were identified, 20 of which met the eligibility criteria for the meta‐analysis. Our pooled meta‐analyses showed that compared with controls, oral MA as an add‐on therapy was associated with significantly lower SCORAD scores (MD = −5.30, 95% CI −8.50, −1.55, p < 0.01, I ( 2 ) = 81%). However, adverse events, pruritus scores, quality of life, and frequency of TCS use showed no significant difference in this meta‐analysis study (p > 0.05). CONCLUSIONS: This meta‐analysis showed that MA plus TCS could be an effective and safe treatment for patients with AD to relieve relevant symptoms, which might be used as an add‐on therapy in the treatment of AD. However, due to the limited number of studies, results should be interpreted with caution. Further studies with a larger sample size are needed to explore the optimal protocol of MA plus TCS.