The effect of probiotic (Clostridium butyricum) on adult patients with atopic dermatitis: a retrospective cohort study from TriNetX

Background

Previous research on probiotics has mainly focused on eczema in infants and pregnant women, with limited benefits observed in adults. Miyarisan, a probiotic known for supporting gut barrier function, has not been extensively studied for its effects on eczema in adult populations.

Methods

We used the TriNetX global network (2014–2024) to compare Miyarisan users with non-users among eczema or dermatitis patients. Propensity score matching (PSM) reduced bias, and hazard ratios (HRs) with 95 % confidence intervals (CIs) and Kaplan-Meier curves assessed skin outcomes based on the SCORAD index. Subgroup analyses explored variations by sex, age, and medication refill frequency, with a sensitivity analysis focusing on atopic dermatitis patients.

Results

Following 1:1 PS M, the study analyzed 1600 cases in each group (Miyarisan users and non-users) without difference between baseline variables. The incidence of itching (HR = 0.372, 95 % CI: 0.287–0.481, p < 0.001), redness (HR = 0.065, 95 % CI: 0.040–0.108, p < 0.001), dryness (HR = 0.358, 95 % CI: 0.285–0.449, p < 0.001), swelling (HR = 0.164, 95 % CI: 0.101–0.265, p < 0.001), scratching (HR = 0.426, 95 % CI: 0.296–0.612, p < 0.001), and thickening (HR = 0.325, 95 % CI: 0.225–0.467, p < 0.001) were significantly lower in the Miyarisan group compared to the non-Miyarisan group. These benefits were consistent across different gender and age subgroups. According to individual SCORAD measures, reduced skin redness was consistently observed across all subgroups. When focusing on atopic dermatitis, Miyarisan users also showed a lower risk of adverse skin outcomes, similar to patients with eczema or dermatitis.

Conclusion

Miyarisan use in adults may reduce the recurrence of eczema or dermatitis, with consistent benefits across both sex and age groups. These findings are also observed in patients with atopic dermatitis.