A Multi-Hospital Comparative Study on the Efficacy of Probiotics Versus Placebo in Preventing Antibiotic-Associated Diarrhea in Adult Patients.

BACKGROUND: Antibiotic-associated diarrhea (AAD) is a prevalent complication of antibiotic therapy, attributed to disruptions in gut microbiota. Probiotics are increasingly studied for their potential in preventing AAD by restoring microbial balance. OBJECTIVE: The aim of this investigation was to assess the efficacy of probiotics in reducing AAD in adult patients when compared to a placebo. METHODOLOGY: This research was conducted from March 2023 to March 2024 using a randomized, placebo-controlled design at multiple institutions: Khyber Teaching Hospital, Peshawar; Prime Teaching Hospital, Peshawar; Mufti Mahmood Memorial Teaching Hospital, Dera Ismail Khan; Shalamar Hospital, Lahore; University Hospitals of Leicester; and DHQ Teaching Hospital Kohat, enrolling 340 adult patients prescribed systemic antibiotics. Eligible participants were aged 18 years and older, while those with chronic diarrhea, inflammatory bowel disease, immunodeficiency, recent probiotic or antibiotic use, or inability to provide informed consent were excluded. The sample size was calculated using WHO guidelines, resulting in a target of 340 to ensure adequate power. Participants were randomized to receive either probiotics (Lactobacillus rhamnosus GG and Bifidobacterium longum BB536) or placebo, administered within 24 hours of starting antibiotics. Daily monitoring of bowel habits and symptoms was performed using standardized diaries, and adherence was evaluated through pill counts. Statistical analyses were performed using IBM SPSS Statistics for Windows, Version 27 (Released 2020; IBM Corp., Armonk, New York, United States), comparing the incidence, severity, and duration of AAD between groups, with a significance threshold of p < 0.05. RESULTS: In the probiotic group, 31 patients (18.23%) developed AAD compared to 53 patients (31.17%) in the placebo group (p=0.01). Among those with AAD, the probiotic group experienced a shorter duration (mean 3.5 ± 1.2 days) compared to placebo (mean 5.1 ± 1.8 days, p=0.002). Adherence rates were high in both groups (probiotic: 96.4%, placebo: 95.9%). Significant improvements in bowel habits were reported more frequently in the probiotic group (77.06%) than placebo (50.59%, p=0.02). The hospital stay duration was similar between groups (probiotic: mean 7.8 ± 2.1 days, placebo: mean 8.3 ± 2.4 days, p=0.15). CONCLUSION: Probiotics significantly reduced the incidence and duration of AAD compared to placebo, with high adherence and favorable patient-reported outcomes.