Key message: moderate quality evidence suggests that probiotics are both safe and effective for preventing Clostridium difficile-associated diarrhoea.
It’s no surprise that a new Cochrane Reviews are systematic reviews. In systematic reviews we search for and summarize studies that answer a specific research question (e.g. is paracetamol effective and safe for treating back pain?). The studies are identified, assessed, and summarized by using a systematic and predefined approach. They inform recommendations for healthcare and research. made headline news on the BBC’s health pages last week and was featured in many other health news reports too, as its focus was the use of probiotics to prevent Clostridium difficile-associated diarrhoea (CDAD) in people taking antibiotics. These medicines can upset the normal healthy balance of organisms in the gut and open the door to infection, often by C.difficile bacteria. It’s a very common side-effect and one you may well have experienced. Perhaps you’ve also bought probiotic supplements from your health food shop or supermarket. These are products containing live micro-organisms which, when taken in adequate amounts, offer a health benefit. They’re not to be confused with prebiotics, which are the food nutrients which feed the “good bacteria” in our bodies.
Infection with C.difficile results in considerable costs in Something done with the aim of improving health or relieving suffering. For example, medicines, surgery, psychological and physical therapies, diet and exercise changes. and for the person infected the consequences range from no symptoms to diarrhoea, colitis or even death. Probiotics are BIG business and there will be much interest in this review from those involved in producing and selling probiotic products as well as those funding, prescribing and taking antibiotics.
The review, from the Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders Group, looked at evidence from Randomization is the process of randomly dividing into groups the people taking part in a trial. One group (the intervention group) will be given the intervention being tested (for example a drug, surgery, or exercise) and compared with a group which does not receive the intervention (the control group). A trial in which a group (the ‘intervention group’) is given a intervention being tested (for example a drug, surgery, or exercise) is compared with a group which does not receive the intervention (the ‘control group’). (RCTs) on the The ability of an intervention (for example a drug, surgery, or exercise) to produce a desired effect, such as reduce symptoms. and Refers to serious adverse effects, such as those that threaten life, require or prolong hospitalization, result in permanent disability, or cause birth defects. of probiotics for preventing CDAD in adults and children. They were able to include 23 RCTs with 4213 people taking antibiotics for any reason, with Data is the information collected through research. which could be combined in a The use of statistical techniques in a systematic review to combine the results of included studies. Sometimes misused as a synonym for systematic reviews, where the review includes a meta-analysis. .
What did they find?
- Probiotics reduced the A way of expressing the chance of an event taking place, expressed as the number of events divided by the total number of observations or people. It can be stated as ‘the chance of falling were one in four’ (1/4 = 25%). This measure is good no matter the incidence of events i.e. common or infrequent. of CDAD, by 64%. 2% of the probiotic group got CDAD compared with 5.5% of the control group. This suggests that 29 people need to be treated to prevent one case of CDAD
- Probiotics did not reduce the The number of new occurrences of something in a population over a particular period of time, e.g. the number of cases of a disease in a country over one year. of C.difficile infection
- Probiotics reduced the risk of side effects by 20%. In both groups side effects included stomach cramps, feeling sick and taste disturbance
- Limited data from three RCTs found no difference in length of time in hospital
How good is the evidence?
Overall, the evidence was judged to be of moderate quality. The low risk of Any factor, recognised or not, that distorts the findings of a study. For example, reporting bias is a type of bias that occurs when researchers, or others (e.g. drug companies) choose not report or publish the results of a study, or do not provide full information about a study. studies suggested a stronger protective effect of probiotics than the high risk of bias studies. Looking at the data in various ways, to explore the possible effect of missing data for example, did not weaken the results and the reviewers judge that the evidence warrants modest confidence in the findings that taking probiotics significantly reduces your risk of CDAD but doesn’t lower the risk of infection. There was a lot of variation in descriptions of side effects; again the reviewers judged that overall the data on side effects is of moderate quality.
So what does this change?
In a press release, lead researcher Bradley Johnston of The Hospital for Sick Children Research Institute in Toronto, Canada said that giving probiotics to people on antibiotics “…could have an immediate impact on patient Outcomes are measures of health (for example quality of life, pain, blood sugar levels) that can be used to assess the effectiveness and safety of a treatment or other intervention (for example a drug, surgery, or exercise). In research, the outcomes considered most important are ‘primary outcomes’ and those considered less important are ‘secondary outcomes’., especially in outbreak settings.” He cautioned “we still need to establish the probiotic strains and doses that provide the best results, and determine the safety of probiotics in immunocompromised patients.”
Further, the review suggests that probiotics prevent symptoms of infection or limit the infection, rather than preventing the infection itself; and this is something that future research could explore, possibly throwing some light on how probiotics prevent CDAD too.
Goldenberg JZ, Ma SSY, Saxton JD, Martzen MR, Vandvik PO, Thorlund K, Guyatt GH, Johnston BC. Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children. Cochrane Database of In systematic reviews we search for and summarize studies that answer a specific research question (e.g. is paracetamol effective and safe for treating back pain?). The studies are identified, assessed, and summarized by using a systematic and predefined approach. They inform recommendations for healthcare and research. 2013, Issue 5. Art. No.: CD006095. DOI: 10.1002/14651858.CD006095.pub3.
Cochrane summary of this review http://summaries.cochrane.org/CD006095/the-use-of-probiotics-to-prevent-c.-difficile-diarrhea-associated-with-antibiotic-use
BBC News Health Probiotics ‘may help when on antibiotics’ An investigation of a healthcare problem. There are different types of studies used to answer research questions, for example randomised controlled trials or observational studies. says. 31st May 2013 http://www.bbc.co.uk/news/health-22717273#?utm_source=twitterfeed&utm_medium=twitter