Download the Free Unbound MEDLINE PubMed App to your smartphone or tablet.
Available for iPhone, iPad, iPod touch, and Android.
Am J Gastroenterol [journal]
- Fear of GI Symptoms has an Important Impact on Quality of Life in Patients With Moderate-to-Severe IBS. [JOURNAL ARTICLE]
- Am J Gastroenterol 2014 Sep 16.
OBJECTIVES:Because irritable bowel syndrome (IBS) is a functional medical condition for which there is no curative therapy, treatment goals emphasize relieving gastrointestinal (GI) symptoms and optimizing the quality of life (QOL). This study sought to characterize the magnitude of the associations between QOL impairment, fear of IBS symptoms, and confounding variables.METHODS:Subjects included 234 Rome III-diagnosed IBS patients (mean age, 41 years, 79%, female) without comorbid organic GI disease who were referred to two specialty care clinics of an National Institutes of Health trial for IBS. Subjects completed a testing battery that included the IBS-specific QOL (IBS-QOL), SF-12 (generic QOL), the UCLA GI Symptom Severity Scale, the Visceral Sensitivity Index, Trait Anxiety Inventory, and Brief Symptom Inventory.RESULTS:Multiple linear regression was used to develop a model for predicting QOL. Data supported an overall model that included sociodemographic, clinical (e.g., current severity of GI symptoms), and psychosocial (e.g., fear of GI symptoms, distress, neuroticism) variables, accounting for 48.7% of the variance in IBS-QOL (F=15.1, P <0.01). GI symptom fear was the most robust predictor of IBS-QOL (β=-0.45 P <0.01), accounting for 14.4% of the total variance.CONCLUSIONS:Patients' fear that GI symptoms have aversive consequences, is a predictor of QOL impairment that cannot be fully explained by the severity of their GI symptoms, overall emotional well-being, neurotic personality style, or other clinical features of IBS. An understanding of the unique impact that GI symptom fears have on QOL can inform treatment planning and help gastroenterologists to better manage more severe IBS patients seen in tertiary care clinics.Am J Gastroenterol advance online publication, 16 September 2014; doi:10.1038/ajg.2014.241.
- A Prospective Study of the Effect of Bowel Movement Frequency, Constipation, and Laxative Use on Colorectal Cancer Risk. [EDITORIAL]
- Am J Gastroenterol 2014 Sep 16.
OBJECTIVES:Constipation and laxative use have been hypothesized to increase colorectal cancer (CRC) risk, but existing epidemiologic studies have been inconclusive. To address this issue, the authors prospectively examined the association between CRC incidence and constipation, non-fiber laxative use, and fiber laxative use among 75,214 participants of the VITamins And Lifestyle study.METHODS:Information on bowel movement frequency as well as average 10-year non-fiber laxative use, fiber laxative use, and constipation was ascertained by means of a questionnaire. Patients were followed from the time of receipt of the baseline questionnaire (2000-2002) until 2008 for CRC incidence, over which time 558 incident CRC cases occurred. Cox proportional hazard models were used to estimate the multivariate-adjusted hazard ratios (HRs) and 95% confidence intervals (95% CI).RESULTS:Compared with individuals who used non-fiber laxatives less than once per year, the HRs associated with low (1-4 times per year) and high (≥5 times per year) use were 1.49 (95% CI: 1.04-2.14) and 1.43 (95% CI: 0.82-2.28), respectively (Ptrend=0.05). HRs for CRC were statistically significantly decreased and lowest in individuals who reported using fiber laxatives often (4+ days per week for 4+ years) vs. those who reported no use (HR=0.44; 95% CI: 0.21-0.95), although the trend was not significant (Ptrend=0.19). No statistically significant associations between bowel movement frequency or constipation and CRC risk were observed.CONCLUSIONS:Findings from this study suggest that risk for CRC increases with non-fiber laxative use and decreases with fiber laxative use. However, further observational and experimental studies are needed to clarify these relationships before drawing conclusions about the preferred treatment of constipation.Am J Gastroenterol advance online publication, 16 September 2014; doi:10.1038/ajg.2014.233.
- Antibiotics Associated With Increased Risk of New-Onset Crohn's Disease But Not Ulcerative Colitis: A Meta-Analysis. [REVIEW]
- Am J Gastroenterol 2014 Sep 16.
OBJECTIVES:The objective of this study was to perform a meta-analysis investigating antibiotic exposure as a risk factor for developing inflammatory bowel disease (IBD).METHODS:A literature search using Medline, Embase, and Cochrane databases was performed to identify studies providing data on the association between antibiotic use and newly diagnosed IBD. Included studies reported Crohn's disease (CD), ulcerative colitis (UC), or a composite of both (IBD) as the primary outcome and evaluated antibiotic exposure before being diagnosed with IBD. A random-effects meta-analysis was conducted to determine overall pooled estimates and 95% confidence intervals (CIs).RESULTS:A total of 11 observational studies (8 case-control and 3 cohort) including 7,208 patients diagnosed with IBD were analyzed. The pooled odds ratio (OR) for IBD among patients exposed to any antibiotic was 1.57 (95% CI 1.27-1.94). Antibiotic exposure was significantly associated with CD (OR 1.74, 95% CI 1.35-2.23) but was not significant for UC (OR 1.08, 95% CI 0.91-1.27). Exposure to antibiotics most markedly increased the risk of CD in children (OR 2.75, 95% CI 1.72-4.38). All antibiotics were associated with IBD, with the exception of penicillin. Exposure to metronidazole (OR 5.01, 95% CI 1.65-15.25) or fluoroquinolones (OR 1.79, 95% CI 1.03-3.12) was most strongly associated with new-onset IBD.CONCLUSIONS:Exposure to antibiotics appears to increase the odds of being newly diagnosed with CD but not UC. This risk is most marked in children diagnosed with CD.Am J Gastroenterol advance online publication, 16 September 2014; doi:10.1038/ajg.2014.246.
- Opioid-Induced Bowel Dysfunction: Epidemiology, Pathophysiology, Diagnosis, and Initial Therapeutic Approach. [REVIEW]
- Am J Gastroenterol 2014 Sep 10; 2(1):31-37.
Opioids affect motor and sensory function throughout the gastrointestinal tract, and are frequently associated with a number of gastrointestinal symptoms including constipation, which impairs the quality of life and may limit the dose of opioid or result in discontinuation altogether. Patients with opioid-induced constipation should be assessed by careful history and physical examination, and in some cases where the diagnosis is unclear with select diagnostic tests. Few clinical studies have been conducted to assess the efficacy of various treatments. However, it is generally recommended that first-line therapy begin with opioid rotation, as well as with low-cost and low-risk approaches such as lifestyle changes, consumption of fiber-rich food, stool softeners, and laxatives.
- The Narcotic Bowel Syndrome: A Recent Update. [REVIEW]
- Am J Gastroenterol 2014 Sep 10; 2(1):22-30.
OBJECTIVES:The paradoxical development of chronic abdominal pain is an underrecognized side effect of opioid use. Narcotic bowel syndrome (NBS), occurring in a small proportion of chronic opioid users, consists of chronic or intermittent abdominal pain, which often increases in severity despite continued or escalating dosages of opioids prescribed to relieve pain.METHODS:A PubMed search was conducted using terms such as "narcotic bowel syndrome" and "opioid hyperalgesia" through January 2014.RESULTS:Abdominal pain is the defining symptom of NBS and is thought to be mediated by central nervous system dysfunction; it should be distinguished from the peripheral side effects of opioids, such as nausea, bloating, intermittent vomiting, abdominal distension, and constipation. This latter cluster of symptoms is called opioid bowel dysfunction, although it may co-occur with NBS. Hypothesized mechanisms of the central effects of opioids on nociception in NBS include spinal cord inflammation and dysfunction in opioid receptor activity and related neuroanatomical substrates. With continued use, ∼6% of patients taking narcotics chronically will develop NBS, with profound consequences in terms of daily function. The primary management paradigm for NBS is a structured opioid withdrawal program accompanied by centrally acting adjunctive therapy comprising antidepressants, benzodiazepines, and clonidine to target pain, anxiety, and depression, and prevent withdrawal effects, in addition to peripherally acting agents such as laxatives (e.g., osmotic laxatives and chloride channel activators) to control transient constipation. Such structured withdrawal programs have been prospectively evaluated in small clinical trials and have met with considerable success in the short term.CONCLUSIONS:Because rates of NBS are likely to rise, integrated intensive pharmacotherapy and psychosocial interventions are needed to help patients with NBS go off and stay off opioids. These programs will likely also reduce comorbid psychopathology and lead to adequate pain control and improved quality of life.
- Molecular Physiology of Enteric Opioid Receptors. [REVIEW]
- Am J Gastroenterol 2014 Sep 10; 2(1):17-21.
Opioid drugs have powerful antidiarrheal effects and many patients taking these drugs for chronic pain relief experience chronic constipation that can progress to opioid-induced bowel dysfunction. Three classes of opioid receptors are expressed by enteric neurons: μ-, δ-, and κ-opioid receptors (MOR, DOR, and KOR). MOR and DOR couple to inhibition of adenylate cylase and nerve terminal Ca(2+) channels and activation of K(+) channels. These effects reduce neuronal activity and neurotransmitter release. KOR couples to inhibition of Ca(2+) channels and inhibition of neurotransmitter release. In the human gastrointestinal tract, MOR, DOR, and KOR link to inhibition of acetylcholine release from enteric interneurons and purine/nitric oxide release from inhibitory motorneurons. These actions inhibit propulsive motility. MOR and DOR also link to inhibition of submucosal secretomotor neurons, reducing active Cl(-) secretion and passive water movement into the colonic lumen. These effects account for the constipation caused by opioid receptor agonists. Tolerance develops to the analgesic effects of opioid receptor agonists but not to the constipating actions. This may be due to differential β-arrestin-2-dependent opioid receptor desensitization and internalization in enteric nerves in the colon compared with the small intestine and in neuronal pain pathways. Further studies of differential opioid receptor desensitization and tolerance in subsets of enteric neurons may identify new drugs or other treatment strategies of opioid-induced bowel dysfunction.
- The Use of Opioid Analgesics for Chronic Pain: Minimizing the Risk for Harm. [REVIEW]
- Am J Gastroenterol 2014 Sep 10; 2(1):3-8.
Chronic noncancer pain is common and consequential, affecting ∼100 million people in the United States alone and costing, when direct and indirect costs are combined, in excess of $635 billion. For certain individuals, opioids may be an effective option for the management of chronic pain; however, a series of critical decisions must be made before prescribing opioids to ensure that their potential benefits and possible risks are appropriately and realistically addressed. A thorough history, physical examination, and appropriate testing, including an assessment of risk for substance abuse, misuse, or addiction, should be conducted in patients who are being considered for opioid therapy. Proactively developing a treatment plan that matches the needs and expectations of the patient, while minimizing the potential for substance abuse, is central to the success of pain management. Current standard of care suggests that for most patients, a trial of nonopioid therapies should generally be tried first. There is no single opioid of choice that universally provides the best outcomes for all patients; thus, it is critical for the health-care practitioner to become familiar with the available subclasses, formulations, and modes of administration, and base the treatment plan on clinical experience with the drug, prior patient experience, the availability of the formulation, and cost and coverage. Pain is a dynamic phenomenon in that its characteristics and response to treatment evolve over time, as does the patient's general health state. Both positive and negative changes over time may necessitate a change in medication. Opioids can be prescribed safely and effectively, and when used with appropriate attention to individual patient characteristics may have a positive impact on pain and function. When contemplating initiation of opioid analgesics, clinicians would do well to make it clear to their patient that they will be prescribed on a trial basis with a clear exit strategy for discontinuing such treatment if there is no clear benefit including lack of analgesia, insurmountable adverse effects, and/or frank misuse or abuse of the prescribed drug.
- Introduction: opioid-induced constipation. [Journal Article]
- Am J Gastroenterol 2014 Sep 10; 2(1):2.
- Continuing Medical Education: September 2014. [REVIEW]
- Am J Gastroenterol 2014 Sep 10; 2(1):1.