Relative Efficacy of Medications for Irritable Bowel Syndrome with Constipation

A recent systematic review and network meta-analysis (CJ Black, et al. Clin Gastroenterol Hepatol 2020; 18: 1238-39) reviewed the relative efficacy of medications for irritable bowel syndrome with constipation. In total, the 14 trials randomized 9113 patients.

Key points:

  • All treatments were significantly more effective than placebo
  • Linaclotide was ranked most effective; however, indirect comparison of active treatments revealed no significant differences between the individual drugs

Prevalence of Rome IV Functional Bowel Disorders in Adults (US, UK, Canada) & Largest Study to Date on Hydroxychloroquine for COVId-19

OS Palsson et al. Gastoenterol 2020; 158: 1262-73.  The authors note that the switch from Rome III to Rome IV criteria reduces the prevalence of IBS by half, but increases the prevalence of functional constipation and functional diarrhea.

Full text PDF: Prevalence of Rome IV Functional Bowel Disorders Among Adults in the United States, Canada, and the United Kingdom



Little is known about the population prevalence or demographic distributions of Rome IV functional bowel disorders (FBDs) or their effects on quality of life. We examined these in a multinational survey.


We analyzed data from a population-based [online] survey of adults in the United States, Canada, and United Kingdom (5931 valid responders; 49.2% female; mean age, 47.4 years; range, 18-92 years). The survey included the Rome IV Diagnostic Questionnaire, Rome III irritable bowel syndrome (IBS) and constipation questions, and the SF-8 quality of life questionnaire.


The prevalence values of census-adjusted Rome IV FBDs were similar among the 3 countries; ranges were: 4.4%-4.8% for IBS, 7.9%-8.6% for functional constipation, 3.6%-5.3% for functional diarrhea, 2.0%-3.9% for functional bloating or distention, 1.1%-1.9% for opioid-induced constipation, 7.5%-10.0% for unspecified FBDs, and 28.6%-31.7% for any Rome IV FBD. FBDs were less common in older individuals, and all except functional diarrhea were more common in women. IBS was only half as prevalent by Rome IV as by Rome III criteria (4.6% vs 9.0% overall), primarily due to higher Rome IV minimum pain frequency. Functional diarrhea and functional constipation were more prevalent by Rome IV than Rome III criteria. Subjects with FBD had significant reductions in quality of life and reported more gastrointestinal doctor consultations than other subjects.


More than 1 in 4 adults in the general population meet the Rome IV criteria for FBDs. These disorders affect quality of life and increase use of gastrointestinal health care. The switch from Rome III to Rome IV criteria reduces the prevalence of IBS by half, but increases the prevalence of functional constipation and functional diarrhea.

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From @EricTopol: Just published @TheLancet The largest study of hydroxychloroquine shows a significant increase in death (~35%) and >2-fold increase of serious heart arrhythmias. ~96,000 patients, ~15,000 on HCQ or CQ from 671 hospitals, 6 continents.

More Jokes:

Great Issue: We Need More Negative Studies (Published)

A recent ACG “Negative Issue” had some terrific articles –thanks to Ben Gold for sharing his issue.

Here are a few of the studies:

  1. Buspirone had similar efficacy as placebo in a randomized clinical trial for childhood functional abdominal pain, (n=117)  Full text: Comparison of the Efficacy of Buspirone and Placebo in Childhood Functional Abdominal Pain Key finding: Treatment response rates for buspirone and placebo were 58.3% and 59.6% at week 4 (P = 0.902) and 68.1% and 71.1% at week 12 (P = 0.753), respectively.
  2. IBS does not increase mortality in a nationwide cohort study (>300,000 in study)  Full text: Mortality Risk in Irritable Bowel Syndrome Key finding: After adjustment for confounders, IBS was not linked to mortality (HR = 0.96; 95% CI = 0.92–1.00) …and patients with IBS not undergoing a colorectal biopsy were at no increased risk of death (HR = 1.02; 95% CI = 0.99–1.06).
  3. Mongerson was not effective for active Crohn’s disease in a large phase 3 study, n=701 Full text: Mongersen (GED-0301) for Active Crohn’s Disease Key finding: The primary endpoint, clinical remission achievement (CD Activity Index score <150) at week 12, was attained in 22.8% of patients on GED-0301 vs 25% on placebo (P = 0.6210). At study termination, proportions of patients achieving clinical remission at week 52 were similar among individual GED-0301 groups and placebo.
  4. Treatment of H pylori did not increase the risk of C difficile infection (retrospective study)  Full text: Treatment of Helicobacter pylori & Clostridium difficile  Key finding: Of these 38,535 patients with H pylori based on endoscopic pathology, urea breath testing, or stool antigen, 284 (0.74%) had subsequent CDI. Those who developed CDI were less likely to have received treatment for HP within the VHA (66.2% vs 74.8%, P < 0.001)
  5. Percutaneous liver biospy was not safer when done by experienced clinician compared to a fellow, n=212 biopsies  Full text: Major Complications of Pediatric Percutaneous Liver Biopsy Do Not Differ Among Physicians With Different Degrees of Training  Key finding: No significant differences were found between groups (fellows vs staff) regarding number of punctures (median of 1.7 for both), nonrepresentative biopsies (4.2% vs 2.6%), and hemoglobin drop (median of 0.7 vs 0.5 g/L).  Interestingly, in the discussion, the authors assert: “previous studies do not support the conclusion that ultrasound-guided biopsies are superior in terms of safety or adequacy when compared with the use of ultrasound to mark the puncture” (this is based on a study referenced from 2007:  J Gastroenterol Hepatol 2007;22(9):1490–3.)  However, given that severe complications from liver biopsy are infrequent, this current study may be underpowered to detect a small difference between experienced clinicians and fellows.

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It’s come to this:  Link: YouTube: Dirty Dancing Remake -Safest with a Lamp (this link is for Bernsie). 4 minute video.

PERSUADE Study: I Guarantee That It Will …

Peppermint oil (PO) products have been promoted for irritable bowel syndrome (IBS) for quite a long time.  When I have recommended PO as a possible treatment, I frequently say that “I guarantee that it will….give you fresh breath.  It might help your stomach symptoms.”

A recent randomized, double-blind “PERSUADE” study (Zsa Zsa R. M. Weerts et al Gastroenterol 2020; 158: 123-36) shows that PO likely has some efficacy for stomach symptoms in IBS. This trial enrolled 189 patients & 178 completed study (mean age, 34 years, 78% female) from the Netherlands.  Subjects were divided in three groups -instructed to take the study capsule 3/day for 8 weeks:

  • 182 mg small-intestinal release PO-SI
  • 182 mg ileocolonic release PO-IC
  • Placebo

The primary endpoint was at least a 30% decrease in the weekly average of worst daily abdominal pain

Key findings:

  • The primary endpoint did NOT differ significantly between the three groups: PO-SI with 46.8%, PO-IC with 41.3%, and Placebo with 34.4% response.
  • The PO-SI but not PO-IC was associated in secondary improvements compared to placebo in abdominal pain (P=.06), discomfort (P=.02), and IBS severity (P=.02).
  • Adverse events were mild with PO, but more common than placebo. Adverse events included heartburn, belching, and headache.
  • The authors calculate that the number needed to treat with PO-SI would be 8 which is higher than recent ACG monograph which suggested an NNT of 4 (Am J Gastroenterol 2018; 113: 1-18).  Even an NNT of 8 compares favorably with other treatments: linaclotide 6, plecanatide 10, and eluxadoline 12.5.


  • the studied population was mainly young adult, predominantly white and female; thus the findings may not be generalized to other groups
  • the peppermint smell could have undermined blinding despite presentation in capsule form
  • relatively short duration study

The associated editorial by BD Cash (pgs 36-37) notes that PO medicinal use began in 1753 by Carl Linnaeus.  PO is thought to work via smooth muscle calcium channel antagonism.  The findings of working in the small intestine and not ileocolonic release could “spur additional therapeutic development.”

My take (borrowed in part from editorial): “These results reaffirm that PO can improve viscerosensory symptoms of IBS …and is well-tolerated… [It is] clearly not a gangbuster as a monotherapy.”  While the findings show modest effect, the findings are supported by a “robust” study as this is the first randomized, double-blind placebo-controlled clinical trial of PO.

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Also, fidaxomicin has received FDA approval for pediatric use for C diff infections: