Top POEMs of 2012: Miscellaneous

Probiotics Decrease Antibiotic-Associated Diarrhea Risk

Clinical question: Does the concurrent use of probiotics decrease the risk of antibiotic-associated diarrhea in adults and children?

Bottom line: Probiotics -- live organisms thought to re-establish gastrointestinal flora -- are effective in decreasing the likelihood of antibiotic-associated diarrhea in adults and children. This approach is also effective when using multiple antibiotics to eradicate Helicobacter pylori. It's not clear from this analysis whether one type of bacterium is better than another. (LOE = 1a)

Reference: Videlock EJ, Cremonini F. Meta-analysis: probiotics in antibiotic-associated diarrhoea. Aliment Pharmacol Ther 2012;35(12):1355-1369.

Study design: Meta-analysis (randomized controlled trials))

Funding source: Self-funded or unfunded

Setting: Various (meta-analysis)

Synopsis: Disrupting the enormous and complex environment of the microbiota in our intestinal tracts with antibiotics is like a tornado decimating a large city; you can't expect the electricity to work the next day. Probiotics are the emergency workers brought into our gastrointestinal infrastructure to get the lights back on. The authors conducting this meta-analysis searched 3 databases, including the Cochrane Controlled Trial Register, followed by searching reference lists of retrieved articles, for double-blind randomized trials comparing the use of a probiotic with placebo in patients receiving antibiotics. They limited their search to articles published in English, which is probably acceptable. Two investigators extracted the data. The authors identified 34 studies of 4138 patients, though approximately one third of the studies had significant risk of bias. The studies included a variety of antibiotics for a variety of illnesses in both inpatient and outpatient settings across all age groups. Probiotics decreased the risk of antibiotic-associated diarrhea by approximately half (relative risk = .53; 95% CI, .44-.63), with one fewer patient reporting diarrhea for every 8 patients treated with a probiotic instead of a placebo (number needed to treat [NNT] = 8; 7-11). The benefit was similar in adults and children. The effectiveness of probiotic treatment was particularly pronounced for the treatment of H. pylori, with an NNT of 5 (4-10). This benefit may be somewhat overstated, given that there was evidence of publication bias (ie, studies not showing a benefit may not have been published). There was also heterogeneity among the study results,

Allen F. Shaughnessy, PharmD, MMedEd
Professor of Family Medicine
Tufts University
Boston, MA

Watching an Injection Increases the Pain

Clinical question: Does watching a painful procedure increase patients' perceptions of the pain and unpleasantness?

Bottom line: Take a hint from dentists, who hide the Novocaine needle behind their back, so that their patients never see the needle about to be thrust into their mouths: Ask patients to look away or close their eyes before getting an injection or having blood drawn. In this experimental study, patients who received a mild electric shock experienced greater pain scores while simultaneously watching a video of a needle pricking a finger, even though they were fully aware that the video was not of their own hand. Expectations are everything. (LOE = 2b)

Reference: Hofle M, Hauck M, Engel AK, Senkowski D. Viewing a needle pricking a hand that you perceive as yours enhances unpleasantness of pain. Pain 2012;153(5):1074-1081.

Study design:  Cohort (prospective)

Funding source: Foundation

Setting: Other

Synopsis: Experiments that mess with our perceptions are very interesting, and this one is no different. The researchers enrolled 28 patients (students) to receive an electric shock to their index finger -- nothing harmful, but enough to be perceived as "painful." Seated, the patients placed their hand on a board, underneath a video screen that showed an image of another hand. The patients were aware that the image was not of their hand though the positioning of the image was the same as the position of their own hand. The video showed the hand being touched by either a needle or a Q-tip at the same time they received the electric shock. Even though they knew it wasn't their own hand, watching the needle prick the video-hand increased their ratings of the pain of the electric shock as compared with watching the Q-tip touch. Pupil dilation, a sign of autonomic reaction to the shock, also increased. Pain intensity was an average 3 to 4 points higher on a scale of 0 to 100 with the image of the needle pain, as were reports of unpleasantness.

Allen F. Shaughnessy, PharmD, MMedEd
Professor of Family Medicine
Tufts University
Boston, MA

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