Probiotics and Recurrent Abdominal Pain

Numerous articles have questioned the effectiveness of probiotics for many of the conditions for which they have been promoted.  A recent systematic review (T Newlover-Delgado, et al. JAMA PediatrPublished online December 28, 2018. doi:10.1001/jamapediatrics.2018.4575) concludes that probiotics “may be effective in the shorter term in improving pain in children with” recurrent abdominal pain (RAP). Thanks to Ben Gold for this reference.

This study extended findings from a 2009 Cochrane review (Huertas-Ceballos AA, et al Cochrane Database Syst Rev 2009; (1):CD003019).  In total, the authors identified 19 eligible studies; of these 15 were not included in the previous review. The most common probiotic studied was Lactobacillus rhamnosus GG in 5 trials.

Key findings:

  • At 0 to 3 months postintervention, ‘based on moderate-quality evidence (odds ratio [OR], 1.63, 95% CI 1.07-2.47; 7 studies, 772 children). The number needed to treat for an additional beneficial outcome was 8.” 
  • There were only 2 studies with results extending 3 to 6 months.  These studies also found reduction in pain in the probiotic-treated children, OR 1.94 (CI 1.10-3.43). 
  • Interestingly, the authors note that fiber-based treatments were not considered more effective than placebo, despite a similar OR of 1.83.  Due to the small number of children in these studies with fiber (n=136), the CI were wide: 0.92-3.65.

The authors discuss some of the limitations such as variations in definitions, choice of probiotic and dosage, and short-term duration.  There is not a discussion of selection bias.  It is quite possible that some negative studies were completed which were not published which could further lower or eliminate the potential benefit.

My take: Probiotics may be helpful for children with recurrent abdominal pain; it is certainly not a panacea.

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Are Probiotics Effective in Changing the Microbiome?

Two recent papers in Cell provide additional questions about the effectiveness of probiotics.

Full Studies:

The coverage of these studies in the media has created some controversy; enough so that the International Scientific Association of Probiotics and Prebiotics disseminated a very critical review:

CLINICAL EVIDENCE AND NOT MICROBIOTA OUTCOMES DRIVE VALUE OF PROBIOTICS

Here is a small excerpt:

Two recent papers have generated much adverse publicity for the probiotic field. Headlines driven by sensationalism, not data, claim “Probiotics labelled ‘quite useless’” (BBC) and “Probiotics ‘not as beneficial for gut health as previously thought’” (The Guardian). The quotes are from author Eran Elinav, who generalizes the study findings to all ‘probiotics’ as a class – a generalization that ignores that specific probiotic are meant for specific purposes…

The scope of these papers is limited to microbiome data; no clinical endpoints are assessed. Without clinical evidence, it is not possible to conclude about the tested probiotic’s usefulness, and it is certainly not possible to conclude about probiotic usefulness in general…. The authors discount the existing body of evidence for probiotic health benefits, including Level 1 placebo-controlled, randomized trials. Cochrane reviews (the gold standard used by physicians and public health policy makers) of the totality of evidence show that specific probiotics can prevent antibiotic associated diarrhea (AAD) and C. difficile diarrhea. This evidence has been translated into evidence-based recommendations for probiotics issued by medical groups. Regardless of an effect on the microbiota, these are established, evidence-based benefits of probiotics.

My take: This controversy points to the problem that probiotics are often considered more effective than the science merits.  While there are some conditions that may respond to probiotics, it should be understood that each probiotic needs to be looked at for each specific clinical scenario.

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Lactobacillus rhamnosus GG Associated with Increased Necrotizing Enterocolitis in Observational Study

A recent retrospective study (AF Kane et al. J Pediatr 2018; 195: 73-9) with 640 VLBW infants found that the probiobiotic, Lactobacillus rhamnosus GG (LGG), was associated with an increased risk of necrotizing enterocolitis (NEC).

LGG supplementation was started at a median age of 6 days at a dose of 2.5 to 5 x 10 to the 9th CFU/day.

Key finding:

  • LGG group had an aOR of 2.10 for developing NEC.  LGG group NEC incidence was 16.8% whereas NEC incidence was 10.2% prior to institution of LGG.

The authors note their findings are in contrast to findings from 38 randomized trials (10,520) which have found that probiotics lowered the risk of NEC.

My take: This study reinforces the need for further studies to identify which factors and probiotic strains are likely to lead to reduced rates of NEC.

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Probiotics for Prevention of Nosocomial Diarrhea in Children

A recent review (I Hojsak et al. JPGN 2018; 66: 3-9) examined published trials regarding the role of probiotics in the prevention of nosocomial diarrhea. The review was conducted by a working group on behalf of ESPGHAN.

Key findings:

  • “Recommendation: If probiotics for preventing nosocomial diarrhea in children are considered, the WG [working group] recommends using L rhamnosus GG (at least 10 to the 9th CFU/day, for the duration of hospital stay).
  • Quality of evidence: Moderate
  • Strength of recommendation: Strong
  • Number needed to treat (in order for beneficial effect in one): 12 patients

The authors do not recommend L reuteri DSM17938 due to lack of efficacy; other probiotics did not receive a recommendation either due to lack of data or lack of efficacy.

It is possible that there have been unpublished negative probiotic studies which would alter the calculation of a beneficial effect.

My take: While the working group recommends L rhamnosus GG if probiotics are used to prevent diarrhea, the absolute benefit is low.

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Probiotics for Colic –2018 Update

There is some debate about whether colic is truly a GI disorder.  A recent commentary (V Sung, MD Cabana. J Pediatr 2017; 191: 6-8) provides some insight.

Key points:

  • “‘Colic’ is a term coined by the ancient Greeks…derived from ‘kolikos,’ meaning crampy pain, sharing its root with the the word colon.”
  • “Since 1994, there have been at least a dozen case-control studies that have indicated differences in the gut microbiota between infants with and without colic.”
  • Studies have had conflicting results with whether calprotectin levels are increased in infants with colic compared with controls.
  • Among probiotics, L reuteri DSM17938 “is the best studied strain.” Despite several studies suggesting efficacy, “the largest and only double-blind randomized trial that included both breastfed and formula-fed infants with colic (n=167) in Australia was ineffective.
  • The commentary reviews a recent study (Fatheree NY et al. J Pediatr 2017; 191: 170-8) “although very small in comparison, adds to this literature, being the second double-blind randomized, placebo-controlled trial of L reuteri DSM17938 shown to be ineffective in breastfed infants with colic.” Sample size =20. “It is the first to document increased fecal calprotectin levels that decrease with reduced crying” …though this “may be reflections of normal levels in healthy young infants, which change over time.”  In addition, this study did not find evidence of systemic inflammation.  The authors speculate that the frequent use of antireflux medications could dampen the effects of probiotics.

My take: We still do not know whether efforts at changing an infant’s microbiome improve clinical outcomes in colic.

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How Good is Your Probiotic for Antibiotic-Associated Diarrhea?

The enthusiasm for probiotics is generally greater than expected based on the data available to support their use for many indications.  This has been discussed several times on this blog (see below).  The reasons why probiotics are sometimes not effective can be related to being poorly regulated/lack rigorous production standards; even in conditions in which there is some effectiveness (eg. antibiotic-associated diarrhea [AAD]), the number of persons needed to treat for one person to benefit is fairly high. Furthermore, as a recent study (A Olek et al. J Pediatr 2017; 186: 82-6) shows, even in conditions like AAD in which probiotics have proven efficacy, the effects may be strain-specific and/or dose-related.

Olek et al showed that Lactobacillus planatarum DSM9843 (LP299V) was NOT beneficial compared to placebo in reducing the incidence of loose/watery stools or mean number of stools among 438 children receiving outpatient antibiotic therapy.

Specifics: This was a prospective, double-blind, randomized, placebo-controlled parallel-group study.  The treatment group received LP299V during antibiotic therapy and for 1 week afterwards.  In addition to monitoring the number of stools, the authors determined the frequency of AAD which they defined according to WHO guidelines (>3 loose/watery stools/24 hours after initiation of antibiotics).  In this study, AAD was confined to study duration rather than over 2 months.

  • Overall, 44.5% of children developed loose/watery stools among placebo group and 39% among probiotic group
  • 4.1% developed AAD among placebo group and 2.8% among LP299V
  • LP299V showed no significant beneficial effects in reducing AAD or loose/watery stools

The authors note that LP299V has been effective in studies involving adult hospitalized patients.  They question whether healthy children, therefore, may be less likely to benefit from probiotics and whether a higher dose could have been more effective.

My take: “Data from clinical studies on probiotics are conflicting” for many conditions, including antibiotic-associated diarrhea.

Lovers Leap, near Ashville (Appalachian Trail)

 

 

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Small Pediatric Study: Probiotic Helping Some with Irritable Bowel Syndrome

In a recent study (O Jadresin et al. JPGN 2017; 64: 925-9), 55 children with functional abdominal pain or irritable bowel syndrome were randomized (prospective, double-blind, placebo-controlled study) to either L reuteri DSM or placebo.

Key findings:

  • The intervention group had more days without pain: median 89.5 days vs. 51 days (P=.029)
  • Abdominal pain was less severe in the intervention group at some time points (second month, and fourth month)
  • The two groups did not differ with regard to duration of abdominal pain, stool type, or absence from school

Limitation: Small number of patients -the estimated samples size was not reached

My take: This study suggests that probiotics may help some pediatric patients with irritable bowel syndrome.  Trying to identify which patients should receive a probiotic and which probiotic should be selected remains unclear.

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