Probiotics do not prevent antibiotic-associated diarrhoea, RCT suggests
Older patients are not protected from antibiotic-associated diarrhoea (AAD) by taking probiotics, the results of a large randomised placebo-controlled trial published online (8 August 2013) in suggest.
Philip Howard, consultant antimicrobial pharmacist at Leeds Teaching Hospital, told PJ Online that the study addresses criticisms of the Hickson study (BMJ 2007), which found that probiotic drinks containing lactobacilli can help to prevent diarrhoea associated with Clostridium difficile infection or antibiotics. ''[The Lancet study] demonstrates that in the current world of cleaner hospitals and improved antimicrobial stewardship, the routine use of probiotics in this high-risk group does not appear to reduce the incidence of Clostridium difficile, said Mr Howard. He added that any hospitals using probiotics could save money by reviewing their practice.
The study recruited inpatients who were 65 years and older and had been exposed to one or more oral or parenteral antibiotic. Half of the patients (n=1,493) were randomised to receive a multistrain preparation of lactobacilli and bifidobacteria in a capsule with a total of 6 x 1010 organisms, and the other half to receive an identical placebo capsule (n=1,488). Both groups took one capsule a day for 21 days and were followed up for eight weeks after stopping antibiotics.
In the microbial group 10.8 per cent of patients developed AAD, compared with 10.4 per cent of patients in the placebo group (relative risk 1.04, 95 per cent confidence interval 0.84–1.28, P=0.71). CDD occurred in 0.8 per cent of patients in the microbial group compared with 1.2 per cent in the placebo group (RR 0.71, CI 0.34–1.47, P=0.35). Furthermore the researchers observed no beneficial effects on abdominal symptoms, length of stay in hospital or other secondary outcomes.
The authors conclude: "Our trial suggests that properties common to many so-called probiotic bacteria, such as the production of lactic acid, are not effective against AAD in older patients."
Results conflict those of previous meta-analyses
Previous meta-analyses have demonstrated a large positive effect of probiotics on the incidence of AAD. In the accompanying commentary these conflicting results are explored by Nick Daneman, division of infectious diseases and clinical epidemiology, Sunnybrook Health Sciences Centre, University of Toronto. He says: "Although the sample size of [this study] was very large, the event rate was much lower than predicted . . . Perhaps the [trial] was negative because its 95 per cent CIs were unable to rule out a potential 16 per cent reduction in occurrence of AAD and a potential 66 per cent reduction in CDD. Alternatively, maybe the results of this single large randomised trial should outweigh the results of any meta-analysis.
"[This] is a large and rigorous negative study, and we must judge whether it can tip the balance of probiotic evidence. Similarly, lactobacilli and bifidobacteria are only two types of non-pathogenic bacteria, and we must consider whether they can really tip the balance of a diverse gut ecosystem."
Citation: Electronicjuice DOI: 10.1211/PJ.2013.11124222
Recommended from Pharmaceutical Press
Pharmaceutical Press is the publishing division of the Royal Electronicjuice, and is a leading provider of authoritative pharmaceutical information used throughout the world.