Evaluating the functional net value of pharmacologic agents in treating irritable bowel syndrome

Evaluating When and Why Patients Discontinue Chronic Therapy for Irritable Bowel Syndrome With Constipation and Chronic Idiopathic Constipation

INTRODUCTION

To inform the patient-centered discussion regarding comparative outcomes with irritable bowel syndrome/chronic idiopathic constipation pharmacotherapy, we evaluated reasons and timing of discontinuation of FDA-approved pharmacotherapy for irritable bowel syndrome and chronic idiopathic constipation in a large observational real-world cohort.

METHODS

We identified patients initiating lubiprostone or linaclotide within the University of Michigan Electronic Medical Record (2012-2016). Medication start and stop dates were determined in manual chart review including detailed review of all documentation including office notes and telephone encounters. A Cox model was constructed to predict the hazard of discontinuation.

RESULTS

On multivariate analysis of 1,612 patients, linaclotide users had a lower risk of discontinuing therapy than lubiprostone users for any reason (hazard ratio [HR] = 0.6, 95% confidence interval [CI] 0.5-0.8). At 3 and 12 months, the overall discontinuation rates were 23% and 43% for lubiprostone compared with 14% and 24% for linaclotide. Over the first year of therapy, more than half of discontinuations due to intolerance occurred in the first 3 months for both drugs. Linaclotide users were more likely to discontinue due to intolerance (HR = 1.6 [95% CI, 1.2-2.3]) but less likely to discontinue due to insufficient efficacy of therapy (HR = 0.5 [95% CI, 0.4-0.8]). IBS diagnosis increased the hazard of discontinuation of lubiprostone relative to linactolide (HR = 1.4, 95% CI, 1.1-1.6). Loss of prescription drug coverage remained a common reason for discontinuation over the first year of therapy.

DISCUSSION

Individuals appear more likely to discontinue lubiprostone than linaclotide overall, but more likely to discontinue linaclotide compared with lubiprostone due to intolerance (mostly diarrhea). Most discontinuations due to intolerance occur in the first 3 months. These results may be useful in individualized treatment selection and enhancing patient knowledge regarding long-term outcomes.

European society of neurogastroenterology and motility guidelines on functional constipation in adults

INTRODUCTION

Chronic constipation is a common disorder with a reported prevalence ranging from 3% to 27% in the general population. Several management strategies, including diagnostic tests, empiric treatments, and specific treatments, have been developed. Our aim was to develop European guidelines for the clinical management of constipation.

DESIGN

After a thorough review of the literature by experts in relevant fields, including gastroenterologists, surgeons, general practitioners, radiologists, and experts in gastrointestinal motility testing from various European countries, a Delphi consensus process was used to produce statements and practical algorithms for the management of chronic constipation.

KEY RESULTS

Seventy-three final statements were agreed upon after the Delphi process. The level of evidence for most statements was low or very low. A high level of evidence was agreed only for anorectal manometry as a comprehensive evaluation of anorectal function and for treatment with osmotic laxatives, especially polyethylene glycol, the prokinetic drug prucalopride, secretagogues, such as linaclotide and lubiprostone and PAMORAs for the treatment of opioid-induced constipation. However, the level of agreement between the authors was good for most statements (80% or more of the authors). The greatest disagreement was related to the surgical management of constipation.

CONCLUSIONS AND INFERENCES

European guidelines on chronic constipation, with recommendations and algorithms, were developed by experts. Despite the high level of agreement between the different experts, the level of scientific evidence for most recommendations was low, highlighting the need for future research to increase the evidence and improve treatment outcomes in these patients.

Presentation and Characteristics of Abdominal Pain Vary by Irritable Bowel Syndrome Subtype: Results of a Nationwide Population-Based Study

INTRODUCTION

Abdominal pain is a cardinal feature of irritable bowel syndrome (IBS); however, differences in abdominal pain among IBS subtypes remain unknown. We aimed to characterize abdominal pain symptoms among established IBS subtypes using data from the National Gastrointestinal (GI) Survey.

METHODS

Individuals participating in the National GI Survey completed National Institutes of Health GI Patient-Reported Outcomes Measurement Information System (GI-PROMIS) questionnaires. Adults meeting modified Rome III IBS criteria and reporting abdominal pain in the previous 7 days were eligible. Outcomes included abdominal pain severity, bothersomeness, interference with daily activities, frequency, and location. Results were stratified by subtype (diarrhea [IBS-D], constipation [IBS-C], and mixed [IBS-M]). Regression models adjusted for demographics and comorbidities.

RESULTS

One thousand one hundred fifty-eight individuals (245 IBS-D, 232 IBS-C, and 681 IBS-M) with active IBS symptoms (defined as abdominal pain in the past 7 days) were included. Demographics were similar among the subtypes except for age, race/ethnicity, education, and marital status. The GI-PROMIS score was lower for IBS-D (percentile score of 68.6, SD = 25.1; P = 0.001) and IBS-M (69.1, SD = 25.1; P < 0.001) compared with IBS-C (75.5, SD = 20.7). Abdominal pain was more bothersome (P = 0.001), caused more interference with daily activities (P = 0.03), and was more frequent (P = 0.047) for individuals with IBS-C compared with individuals with IBS-D. No differences in these domains were seen between individuals with IBS-D and IBS-M. Individuals with IBS-C and IBS-M had more widespread pain compared with those with IBS-D.

DISCUSSION

In this population-based study, we found that abdominal pain characteristics differ between the IBS subtypes. Namely, individuals with IBS-C experience more bothersome, frequent, and diffuse abdominal pain compared with those with IBS-D.

Effect of Repeated Consumption of Partially Hydrolyzed Guar Gum on Fecal Characteristics and Gut Microbiota: A Randomized, Double-Blind, Placebo-Controlled, and Parallel-Group Clinical Trial

Partially hydrolyzed guar gum (PHGG) is a water-soluble dietary fiber and is used in solid and liquid food to regulate gut function. The aim of this study was to investigate effects of PHGG on bowel movements (stool form and frequency), plasma bile acids, quality of life, and gut microbiota of healthy volunteers with a tendency toward diarrhea, i.e., irritable bowel syndrome diarrhea (IBS-D)-like symptoms. A randomized, double-blind, placebo-controlled, and parallel trial was performed on 44 healthy volunteers (22 males, 22 females, 41.9 ± 6.3 years old (average ± SD)) with minimum 7 bowel movements every week, wherein above 50% of their stool was between the Bristol stool scale (BSS) value of 5 and 6. Intake of the PHGG for 3 months significantly improved stool form, evaluated using BSS, and had no effects on stool frequency. BSS was significantly normalized in the group consuming the PHGG compared with the placebo. Comprehensive fecal microbiome analysis by the 16S rRNA-sequence method detected significant changes in the ratio of some bacteria, such as an increase of Bifidobacterium (p < 0.05) in the PHGG group. Our results suggest that intake of PHGG improves human stool form via regulating intestinal microbiota.

Declining Rates of Referral for Irritable Bowel Syndrome Without Constipation at a Tertiary Care Center

BACKGROUND

Irritable bowel syndrome (IBS) is a common chronic disorder of the gastrointestinal tract. Several treatments have been developed, including rifaximin for the treatment of IBS without constipation (non-IBS-C), but no studies have evaluated the effect of these therapies on patient referral rates to tertiary care gastroenterology clinics.

AIM

To assess referral patterns for IBS patients at a tertiary motility clinic over a 10-year period.

METHODS

Data from consecutive patients referred to the clinic during 2006-2016 were analyzed. Trends in the proportion of referrals and prior rifaximin use in IBS-C versus non-IBS-C groups were compared.

RESULTS

A total of 814 adult patients were referred to a single physician panel for IBS-related symptoms. Of these, 776 were included in the study [528 females (68%), average age 45.7 ± 15.9 years), comprising 431 IBS-C (55.5%) and 345 non-IBS-C (44.5%) patients. The proportion of non-IBS-C referrals declined significantly from 53.0% in 2006 to 27.3% in 2016 (Chi-square, p < 0.0001, Cochran-Armitage trend test p = 0.0001), and the proportion of IBS-C referrals increased significantly from 46.9% in 2006 to 72.7% in 2016 (Chi-square, p < 0.0001, Cochran-Armitage trend test p = 0.0004). Non-IBS-C referrals with prior rifaximin use significantly increased from 22.7% in 2006 to 66.7% in 2016 (Cochran-Armitage trend test, p = 0.008).

CONCLUSIONS

The results indicate a significantly declining tertiary care referral rate for non-IBS-C over the past decade. While not directly linked, there has been an increase in rifaximin use in the same population during the same time interval.

Short-course therapy for diarrhea-predominant irritable bowel syndrome: understanding the mechanism, impact on gut microbiota, and safety and tolerability of rifaximin

Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) disorder characterized by abdominal pain that occurs with defecation or alterations in bowel habits. Further classification is based on the predominant bowel habit: constipation-predominant IBS, diarrhea-predominant IBS (IBS-D), or mixed IBS. The pathogenesis of IBS is unclear and is considered multifactorial in nature. GI dysbiosis, thought to play a role in IBS pathophysiology, has been observed in patients with IBS. Alterations in the gut microbiota are observed in patients with small intestinal bacterial overgrowth, and overgrowth may occur in a subset of patients with IBS. The management of IBS includes therapies targeting the putative factors involved in the pathogenesis of the condition. However, many of these interventions (eg, eluxadoline and alosetron) require long-term, daily administration and have important safety considerations. Agents thought to modulate the gut microbiota (eg, antibiotics and probiotics) have shown potential benefits in clinical studies. However, conventional antibiotics (eg, neomycin) are associated with several adverse events and/or the risk of bacterial antibiotic resistance, and probiotics lack uniformity in composition and consistency of response in patients. Rifaximin, a nonsystemic antibiotic administered as a 2-week course of therapy, has been shown to be safe and efficacious for the treatment of IBS-D. Rifaximin exhibits a favorable benefit-to-harm ratio when compared with daily therapies for IBS-D (eg, alosetron and tricyclic antidepressants), and rifaximin was not associated with the emergence of bacterial antibiotic resistance. Thus, short-course therapy with rifaximin is an appropriate treatment option for IBS-D.

Diarrhea-predominant irritable bowel syndrome: Diagnosis, etiology, and new treatment considerations

PURPOSE

To provide an overview of irritable bowel syndrome (IBS), specifically the efficacy and tolerability of treatment options for diarrhea-predominant IBS (IBS-D).

DATA SOURCES

Research articles available via PubMed were reviewed.

CONCLUSIONS

IBS is a chronic multifactorial disorder that has a negative impact on patient-related quality of life. Genetic factors, psychosociologic factors, alterations in the gut microbiota, and changes in immune, motor, and sensory responses to various stimuli all may be involved in the development of IBS. While pharmacologic therapies for IBS-D have historically been limited (e.g., alosetron), newer therapies (eluxadoline and rifaximin), both approved in the United States in 2015, may be considered for appropriate patients for the management of IBS-D.

IMPLICATIONS FOR PRACTICE

Nurse practitioners play an important role in the diagnosis, care, and management of patients with IBS-D. The goals of therapy should be to reach a correct diagnosis before initiating therapy, provide reassurance to the patient, educate the patient on potential treatment options, improve IBS-D symptoms, minimize risk of harm with treatment, and maximize patient-related quality of life. The authors present a treatment algorithm to guide nurse practitioners on the management of patients with IBS-D.

Aminophylline suppresses stress-induced visceral hypersensitivity and defecation in irritable bowel syndrome

Pharmacological therapy for irritable bowel syndrome (IBS) has not been established. In order to find candidate drugs for IBS with diarrhea (IBS-D), we screened a compound library of drugs clinically used for their ability to prevent stress-induced defecation and visceral hypersensitivity in rats. We selected the bronchodilator aminophylline from this library. Using a specific inhibitor for each subtype of adenosine receptors (ARs) and phosphodiesterases (PDEs), we found that both A2BARs and PDE4 are probably mediated the inhibitory effect of aminophylline on wrap restraint stress (WRS)-induced defecation. Aminophylline suppressed maternal separation- and acetic acid administration-induced visceral hypersensitivity to colorectal distension (CRD), which was mediated by both A2AARs and A2BARs. We propose that aminophylline is a candidate drug for IBS-D because of its efficacy in both of stress-induced defecation and visceral hypersensitivity, as we observed here, and because it is clinically safe.

Functional gastrointestinal disorders in 35,447 adults and their association with body mass index

BACKGROUND

Functional gastrointestinal disorders' (FGIDs) associations with body mass index (BMI) have not been thoroughly investigated in the general population.

AIM

To investigate the overlap between functional dyspepsia (FDy), irritable bowel syndrome (IBS), functional constipation (FC) and functional diarrhoea (FDh) and the relationship between BMI and those diagnoses in a large French adult population.

METHODS

Subjects participating in the Nutrinet-Santé cohort study completed a questionnaire based on Rome III criteria. Anthropometrics, socio-demographical and lifestyle data were collected via self-administered questionnaires. Associations between BMI and FGIDs were investigated with multivariate logistic regression.

RESULTS

A total of 35 447 subjects were included in the analysis. Among subjects with FGIDs, 10.4% presented more than one disorder. [FDy coexisted with IBS (23.6%) and FC (15.1%)]. Associations between BMI and FDy differed according to sex. In females, higher odds were observed for underweight and obesity subgroups (OR = 1.26 (95% CI: 0.99-1.59), OR = 1.35 (1.08-1.69), OR = 1.20 (0.81-1.77), OR = 1.47 (0.89-2.42) for underweight, class I, II and III obesity respectively compared with normal BMI), forming a U-shaped relationship confirmed with nonlinear model (P < 0.001). In females, FDh was associated with BMI [OR = 1.05 (1.03-1.07), P < 0.001]. In males, a negative association between BMI and IBS was observed [OR = 0.97 (0.94-0.99), P=0.04]. Other associations were not significant.

CONCLUSIONS

Our study showed an important overlap in FGIDs, supporting the contention of common pathophysiological mechanisms. Relationships between BMI and FGIDs appeared to be sex-dependent. Interaction by sex in the association between BMI and FGIDs should therefore be further explored.