The prevalence of chronic diarrhea among diabetic patients

Downregulation of BDNF-TrkB signaling may contribute to the colonic motility disorders in mice with streptozocin-induced diabetes

BACKGROUND

Brain-derived neurotrophic factor (BDNF) acts as a neuromodulator to regulate gut motility, but the role of BDNF in diabetes-related dysmotility is uncertain. The aim of this study was to investigate the possible involvement of BDNF and its receptor TrkB in the colonic hypomotility of mice with streptozotocin (STZ)-induced diabetes.

METHODS

A single intraperitoneal injection of STZ was used to establish a type 1 diabetes model. An organ bath system was applied to observe the contractile activities of colonic muscle strips. Immunofluorescence and western blotting were performed to evaluate the expression of BDNF and TrkB in the colon. ELISA was used to detect BDNF and SP levels in the serum and colon. The patch-clamp technique was applied to record the currents of L-type calcium channels and large conductance Ca2+ -activated K+ channels on smooth muscle cells.

KEY RESULTS

Compared with healthy controls, diabetic mice showed attenuated colonic muscle contraction (p < 0.001), which was partly reversed by BDNF supplementation. TrkB protein expression was significantly reduced in diabetic mice (p < 0.05). In addition, both BDNF and substance P (SP) levels were decreased, and exogenous administration of BDNF increased SP levels in diabetic mice (p < 0.05). Both the TrkB antagonist and the TrkB antibody inhibited the spontaneous contraction of colonic muscle strips (p < 0.01). Moreover, the BDNF-TrkB signaling system enhanced SP-induced muscle contraction.

CONCLUSIONS

Downregulation of BDNF/TrkB signaling and reduced SP release from the colon may contribute to the colonic hypomotility associated with type 1 diabetes. Brain-derived neurotrophic factor supplementation may have therapeutic potential for diabetes-related constipation.

Constipation in DM are associated with both poor glycemic control and diabetic complications: Current status and future directions

Constipation is a major complications of diabetes mellitus. With the accelerating prevalence of diabetes worldwide and an aging population, there is considerable research interest regarding the altered function and structure of the gastrointestinal tract in diabetic patients. Despite current advances in hyperglycemic treatment strategies, the specific pathogenesis of diabetic constipation remains unknown. Patients with constipation, may be reluctant to eat regularly, which may worsen glycemic control and thus worsen symptoms associated with underlying diabetic bowel disease. This paper presents a review of the complex relationship between diabetes and constipation, exploring the morphological alterations and biomechanical remodeling associated with intestinal motility dysfunction, as well as alterations in intestinal neurons, cellular signaling pathways, and oxidative stress. Further studies focusing on new targets that may play a role in the pathogenesis of diabetic constipation may, provide new ideas for the development of novel therapies to treat or even prevent diabetic constipation.

Novel insights into the pathogenic impact of diabetes on the gastrointestinal tract

Type 2 and type 1 diabetes are common endocrine disorders with a progressively increasing incidence worldwide. These chronic, systemic diseases have multiorgan implications, and the whole gastrointestinal (GI) tract represents a frequent target in terms of symptom appearance and interdependent pathophysiological mechanisms. Metabolic alterations linked with diabetic complications, neuropathy and disrupted hormone homeostasis can lead to upper and/or lower GI symptoms in up to 75% of diabetic patients, with multifactorial involvement of the oesophagus, stomach, upper and lower intestine, and of the gallbladder. On the other hand, altered gastrointestinal motility and/or secretions are able to affect glucose and lipid homeostasis in the short and long term. Finally, diabetes has been linked with increased cancer risk at different levels of the GI tract. The presence of GI symptoms and a comprehensive assessment of GI function should be carefully considered in the management of diabetic patients to avoid further complications and to ameliorate the quality of life. Additionally, the presence of gastrointestinal dysfunction should be adequately managed to improve metabolic homeostasis, the efficacy of antidiabetic treatments and secondary prevention strategies.

[Diabetic gastroenteropathy: modern methods of diagnosis and treatment]

Diabetes mellitus is a chronic disease with a growing prevalence worldwide, however, the prevalence of its complications, including gastroenteropathy, is also increasing. The pathophysiology of diabetic gastroenteropathy (DH) combines hyperglycemia, vagus nerve dysfunction, decreased expression of nitric oxide synthase in the myenteric plexus, changes in the interstitial Cajal cell network, as well as oxidative stress. Clinical signs of DH are gastroesophageal reflux, gastroparesis, constipation, abdominal pain and diarrhea. Among the diagnostic methods are manometry with pH measurement (assessment of esophageal motility), gastric emptying scintigraphy, respiratory test (to assess gastroparesis), aspiration and cultivation of the contents of the jejunum (to diagnose bacterial overgrowth syndrome). To date, there is no definitive treatment for DH - an interdisciplinary approach is aimed at slowing the progression of the disease, relieving symptoms and restoring gastrointestinal function. Patients are recommended a diet low in simple sugars and high in fiber; optimization of glycemic control with a target glycemia of less than 180 mg/dl. As for drug therapy, the use of prokinetics and antiemetics is justified, and in case of excessive bacterial growth syndrome, antibacterial therapy (rifaximin) is carried out. Modern approaches to the treatment of DH are also accumulating, including the use of botulinum toxin, pyloroplasty and electrical stimulation of the stomach in individual patients. Despite the constant development of new treatments, they are not yet able to completely cure DH in the near future, which makes it necessary to conduct further research in this area.

Diabetic gastroenteropathy: An underdiagnosed complication

This article is an extensive review that provides an update on the pathophysiology, symptoms, diagnosis, and treatment of diabetic gastroenteropathy. There is no reported prevalence, but it has been described that patients with type 1 diabetes have a cumulative incidence at 10 years of 5.2%, and type 2 patients, 1%. Also, in the group of type 1 diabetes, it has been observed that women are more likely to present this condition (5.8% vs 3.5%). Many factors are associate with its development (e.g., hyperglycemia, vagal dysfunction, loss of expression of neural nitric oxide synthase in the myenteric plexus, alterations in the Cajal interstitial cell network, and oxidative stress). Gastrointestinal discomfort could be perceived 70% higher in diabetic patients, describing that 25% of diabetic patients experience gastrointestinal symptoms. Diabetic enteropathy could affect any portion of the gastrointestinal tract, but esophageal alterations were described in more than 60% of diabetic patients, also 60% of them present constipation, and 20%, diarrhea. Gastric emptying scintigraphy is useful to evaluate gastroparesis, therefore, gastric retention of more than 60% at 2 h has a sensitivity of 100% and specificity of 20% for diagnosis; however, other studies such as breath tests, with a sensitivity of 89% and a specificity of 80%, or the endoscopic capsule contribute to the diagnosis. There is no cure; however, management must be multidisciplinary, focused on slowing the progression of diabetic gastroenteropathy, reducing symptoms, and restoring function; that includes nutritional recommendation, maintain glucose levels kept below 180 mg/dL, use of prokinetics, anti-emetics; nowadays, it has been special interest in surgical treatment, such as pyloroplasty, also gastric electrical stimulation appears to be another alternative.

Gastrointestinal autonomic neuropathy in diabetes

Gastrointestinal autonomic neuropathy represents an important and diverse, but poorly appreciated, manifestation of diabetic autonomic neuropathy that impacts negatively on quality of life. There is no test to assess gastrointestinal autonomic nerve damage directly in humans; cardiovascular autonomic reflex tests are often used as a surrogate, but are suboptimal. Gastrointestinal symptoms are common in diabetes, but usually correlate only weakly with disordered motility. Diabetic gastroparesis, or abnormally delayed gastric emptying, occurs frequently and is the best characterized manifestation of gastrointestinal autonomic neuropathy. There is a bi-directional relationship between postprandial glycaemia and the rate of gastric emptying. However, autonomic neuropathy can affect the function of any gut segment from the esophagus to the anus. Current management options for gastrointestinal autonomic neuropathy are, for the main part, empirical and sub-optimal.

Gastrointestinal symptoms in pediatric patients with type 1 diabetes mellitus

Background Various gastrointestinal (GI) symptoms are associated with diabetes. Common GI complaints associated with the manifestation of the disease include abdominal pain, diarrhea, nausea, bloating and vomiting. There have been very few studies examining GI problems of pediatric patients with type 1 diabetes mellitus (T1DM). The aims of this study were to find out the prevalence of GI symptoms in pediatric patients with T1DM and to determine the correlation among such symptoms, duration of diabetes and glycemic control. Methods One hundred and thirty-seven (median age 13.2 years, female 45.3%) patients with T1DM were examined. Demographic features, GI symptoms, signs and physical examination findings of the patients were recorded by pediatric gastroenterology specialists for the differential diagnosis and exclusion of other etiologies. Complete blood count, blood glucose, lipid profile, electrolytes, amylase, lipase, celiac antibodies and glycated hemoglobin (HbA1c) levels were evaluated and stool examination was performed. Endoscopy was performed on the patients who had refractory GI complaints. Gastric emptying (GE) time was evaluated using GE scintigraphy. Results Overall, 74 (54%) patients had ≥1 GI complaints. Patients often reported gastroesophageal reflux (32.8%) and abdominal pain (18%). The most significant findings in terms of GI symptoms were determined when patients were classified according to the glycemic control status. Reflux and dyspeptic symptoms were significantly more common in poorly or very poorly controlled diabetic patients (p=0.003 and p=0.004, respectively). Conclusions Diabetes can affect the entire GI tract, and GI symptoms are common in pediatric patients. We recommend that T1DM patients be evaluated for GI symptoms.

The Role of Diabetes Mellitus in Diseases of the Gallbladder and Biliary Tract

BACKGROUND

The increasing prevalence of diabetes mellitus worldwide continues to pose a heavy burden. Though its gastrointestinal impact is appropriately recognized, the lesser known associations may be overlooked.

OBJECTIVE

We aim to review the negative implications of diabetes on the gallbladder and the biliary tract.

METHODS

A MEDLINE® database search of literature was conducted with emphasis on the previous five years, combining keywords such as "diabetes," "gallbladder," and "biliary".

RESULTS

The association of diabetes to the formation of gallstones, gallbladder cancer, and cancer of the biliary tract are discussed along with diagnosis and treatment.

CONCLUSION

Though we uncover the role of diabetic neuropathy in gallbladder and biliary complications, the specific individual diabetic risk factors behind these developments is unclear. Also, in addition to diabetes control and surgical gallbladder management, the treatment approach also requires further focus.

Prevalence of Chronic Constipation and Chronic Diarrhea in Diabetic Individuals in the United States

INTRODUCTION

Diabetic individuals commonly report disordered bowel habits. This study aims to report the prevalence and associated factors of chronic diarrhea (CD) and chronic constipation (CC) in diabetics using a nationally representative sample of US adults.

METHODS

Analyses were performed using data from subjects in the 2009-2010 National Health and Nutrition Examination Survey (NHANES) dataset who completed the Bowel Health Questionnaire. The NHANES dataset provides medical comorbidities, demographics, and dietary habits of a nationally representative group of adult survey participants in the United States. CC and CD were defined by Bristol Stool Form Scale (BSFS) Types 1 & 2 and BSFS Types 6 & 7 as the "usual or most common stool type," respectively, and frequent laxative users were also defined as having CC. Co-variables for all subjects included demographic and lifestyle factors, and co-variables evaluated only in diabetics included treatment and severity markers for diabetes.

RESULTS

We identified 661 diabetic subjects and 4488 non-diabetic subjects. Diabetic subjects (25.8%) reported disordered bowel habits. In unadjusted analysis, CD was more prevalent in diabetics than in non-diabetics (11.2% vs. 6.0%; p < 0.0001); however, the prevalence of CC was not significantly different between groups (14.6% vs. 11.2%; p = 0.126). When adjusting for covariates (e.g., BMI, gender, age, race/ethnicity, education level, etc.), diabetes itself remained associated with CD. Diabetic individuals with CD more frequently used drugs to lower blood sugar, and diabetic subjects with CC more frequently had poor kidney function.

CONCLUSIONS

CD is significantly more prevalent in diabetics than in non-diabetics, whereas CC is not, and the association between CD and diabetes remains significant when adjusting for covariates. Use of medications that lower blood sugar is associated with CD in diabetic individuals, whereas poor kidney function is associated with CC in diabetics.

Diabetes Mellitus and the Colon

OPINION STATEMENT

Diabetes mellitus (DM) can affect the structure and function of the colon promoting commonly encountered lower gastrointestinal symptoms such as constipation, diarrhea, abdominal distention, bloating, and abdominal pain. Specific colonic disorders for which adults with DM are at greater risk include chronic constipation, enteropathic diarrhea, colorectal cancer (CRC), inflammatory bowel disease, microscopic colitis, and Clostridium difficile colitis. Smooth muscle structure and function, density of the interstitial cells of Cajal, and the health and function of the autonomic and enteric nerves of the colon are all potential affected by DM. These effects can in turn lead to alterations in colon motility, visceral sensation, immune function, endothelial function, and the colonic microbiome. The evaluation and treatment for slow transit constipation as well as pelvic floor dysfunction should be considered when constipation symptoms are refractory to initial treatment measures. DM-related medications and small bowel conditions such as celiac disease and small intestinal bowel overgrowth should be considered and excluded before a diagnosis of enteropathic diarrhea is made. Given the higher risk of CRC, adults with DM should be appropriately screened and may require a longer bowel preparation to ensure an adequate evaluation.

Diabetes-induced mechanophysiological changes in the small intestine and colon

The disorders of gastrointestinal (GI) tract including intestine and colon are common in the patients with diabetes mellitus (DM). DM induced intestinal and colonic structural and biomechanical remodeling in animals and humans. The remodeling is closely related to motor-sensory abnormalities of the intestine and colon which are associated with the symptoms frequently encountered in patients with DM such as diarrhea and constipation. In this review, firstly we review DM-induced histomorphological and biomechanical remodeling of intestine and colon. Secondly we review motor-sensory dysfunction and how they relate to intestinal and colonic abnormalities. Finally the clinical consequences of DM-induced changes in the intestine and colon including diarrhea, constipation, gut microbiota change and colon cancer are discussed. The final goal is to increase the understanding of DM-induced changes in the gut and the subsequent clinical consequences in order to provide the clinicians with a better understanding of the GI disorders in diabetic patients and facilitates treatments tailored to these patients.

The value of time-to-onset in statistical signal detection of adverse drug reactions: a comparison with disproportionality analysis in spontaneous reports from the Netherlands

PURPOSE

In pharmacovigilance, the commonly used disproportionality analysis (DPA) in statistical signal detection is known to have its limitations. The aim of this study was to investigate the value of the time to onset (TTO) of ADRs in addition to DPA.

METHODS

We performed a pilot study using individual case safety reports (ICSRs) for three drugs (Cervarix®, nitrofurantoin and simvastatin) from the Lareb spontaneous reporting database. TTO distributions for drug - ADR associations were compared to other ADRs for the same drug and to other drugs for the same ADR using two-sample Anderson-Darling testing. Statistically significant associations were considered true positive (TP) signals if the association was present in the official product information of the drug. Sensitivity and specificity for the TTO method were compared with the DPA method. As a measure of disproportionality, the reporting odds ratio (ROR) was used.

RESULTS

In general, sensitivity was lower, and specificity was higher for the TTO method compared to DPA. The TTO method showed similar sensitivity for all three drugs, whereas specificity was lower for Cervarix®. Eight additional TP signals were found using the TTO method compared to DPA.

CONCLUSIONS

Our study shows that statistical signal detection based on the TTO alone resulted in a limited number of additional signals compared to DPA. We therefore conclude that the TTO method is of limited value for full database statistical screening in our setting. Copyright © 2016 John Wiley & Sons, Ltd.

A Practical Approach to Gastrointestinal Complications of Diabetes

Gastrointestinal symptoms occur frequently among people with diabetes mellitus and are associated with considerable morbidity. Enteropathy, or large bowel dysfunction, includes constipation, diarrhea and fecal incontinence, and is particularly disturbing for many patients. The pathogenesis of diabetic enteropathy is complex, primarily related to gastrointestinal autonomic dysfunction and etiologically associated with chronic hyperglycemia and diabetes duration. Since there are many other non-iatrogenic and iatrogenic causes of the cardinal symptoms of large bowel dysfunction, patients suspected of having diabetic enteropathy require detailed evaluation. The management of patients with diabetic enteropathy is challenging, and often requires a multidisciplinary approach focusing on a combination of symptom mitigation and glycemic control.

Diabetic autonomic neuropathy

Diabetes mellitus is the commonest cause of an autonomic neuropathy in the developed world. Diabetic autonomic neuropathy causes a constellation of symptoms and signs affecting cardiovascular, urogenital, gastrointestinal, pupillomotor, thermoregulatory, and sudomotor systems. Several discrete syndromes associated with diabetes cause autonomic dysfunction. The most prevalent of these are: generalized diabetic autonomic neuropathy, autonomic neuropathy associated with the prediabetic state, treatment-induced painful and autonomic neuropathy, and transient hypoglycemia-associated autonomic neuropathy. These autonomic manifestations of diabetes are responsible for the most troublesome and disabling features of diabetic peripheral neuropathy and result in a significant proportion of the mortality and morbidity associated with the disease.

Predicting Clostridium difficile infection in diabetic patients and the effect of metformin therapy: a retrospective, case-control study

Data on risk factors for Clostridium difficile infection (CDI) in diabetic patients are scarce. Recently, it has been shown that metformin increases the Bacteroidetes/Firmicutes ratio; therefore, it may yield a protective effect against CDI. We aimed to assess risk factors for CDI in diabetic patients beyond antibiotic treatment, and to determine the impact of metformin therapy on the development of CDI in these patients. In this retrospective, case-control study, all consecutive CDI diabetic patients, from January 2009 to December 2013, were included and compared to consecutive diabetic patients without CDI, hospitalized during the same period and in the same departments. Of 7,670 patients tested for C. difficile toxins, 486 were diabetics. Of them, 150 (30.8 %) were positive for C. difficile toxins and 336 (69.1 %) were negative. On multivariate analysis, metformin treatment was associated with a significant reduction in CDI [odds ratio (OR) = 0.58; 95 % confidence interval (CI), 0.37-0.93; p = 0.023], while heart failure was associated with significantly higher rates of CDI (OR = 1.654; 95 % CI, 1.007-2.716; p = 0.047), together with poor functional status, previous hospitalization, and abdominal surgery. Our findings suggest that, in diabetic patients, in addition to the well-recognized risk factors, heart failure is an additional risk factor for CDI, while metformin treatment seems to have a protective effect against the development of CDI. The exact mechanisms underlying this protective effect remain to be fully understood.

Management of colorectal cancer and diabetes

Colorectal cancer is associated with diabetes mellitus and both of these common conditions are often managed together by a surgeon. The surgical focus is usually upon cancer treatment rather than diabetes management. The relationship between colorectal cancer and diabetes is a complex one and can raise problems in both diagnosis and the management of patients with both conditions. This literature review explores the relationship between diabetes, diabetic treatment and colorectal cancer and addresses the issues that arise in diagnosing and treating this patient group. By highlighting these difficulties, this review aims to improve understanding and to provide clearer insight into both surgical and non-surgical management.

Gastrointestinal complications of diabetes

This review provides an overview of the vast gastrointestinal tract complications of diabetes that can occur from the mouth to the anus. The presentation, diagnosis, and management of gastrointestinal disorders, ranging from gastroparesis, celiac disease, and bacterial overgrowth to nonalcoholic fatty liver disease, are reviewed to heighten awareness. When managing care of patients with diabetes, one should keep in mind the potential gastrointestinal complications, as well as the frequent disorders that are not related to diabetes.

[Autonomic peripheral neuropathy]

The mechanisms of dysautonomic disturbances are varied and mostly acquired. They can result from lesions of sympathetic or parasympathetic vegetative fibers located in the peripheral contingent, or in the somatic contingent by demyelination or axonal loss; or more rarely by cellular bodies in the sympathetic or parasympathetic ganglia. Several chronic peripheral neuropathies can be associated with dysautonomia. Only some causes need to be known because they can be clinically significant. Dysautonomia may be seen during chronic acquired neuropathies but also acute or subacute ones. The most frequent cause in the world is the dysautonomia of the diabetes; it affects all the systems; the cardiovascular dysfunction has an impact on the prognosis for survival when it is severe. Hereditary autonomic neuropathies are rare; they can declare themselves very early during the Riley-Day syndrome or very late during amyloid polyneuropathies due to transthyretin gene mutation. The diagnosis can be confirmed by molecular biology. The dysautonomia is frequent and often severe. These neuropathies justify symptomatic treatment to improve quality of life. For some of them, a specific treatment can be proposed to treat the causal affection to try to stop the progression of the disease.

Diabetic gastrointestinal autonomic neuropathy: current status and new achievements for everyday clinical practice

Gastrointestinal symptoms occur frequently among patients with diabetes mellitus and are associated with considerable morbidity. Diabetic gastrointestinal autonomic neuropathy represents a complex disorder with multifactorial pathogenesis, which is still not well understood. It appears to involve a spectrum of metabolic and cellular changes that affect gastrointestinal motor and sensory control. It may affect any organ in the digestive system. Clinical manifestations are often underestimated, and therefore autonomic neuropathy should be suspected in all diabetic patients with unexplained gastrointestinal symptoms. Advances in technology have now enabled assessment of gastrointestinal motor function. Moreover, novel pharmacological approaches, along with endoscopic and surgical treatment options, contribute to improved outcomes. This review summarises the progress achieved in diabetic gastrointestinal autonomic neuropathy during the last years, focusing on clinical issues of practical importance to the everyday clinician.

Evaluating the patient with diarrhea: a case-based approach

The evaluation of the patient with diarrhea can be complex and the treatment challenging. In this article, the definition of diarrhea and the pathophysiologic mechanisms that lead to diarrhea are reviewed. A simplified 5-step approach to the patient with diarrhea is provided and applied in a case-oriented manner applicable to everyday clinical practice. On completion of this article, you should be able to (1) define diarrhea, (2) outline various pathophysiologic mechanisms of diarrhea, and (3) describe a simplified 5-step approach to facilitate the evaluation of diarrhea.

Celiac disease in patients with type-1 diabetes mellitus screened by tissue transglutaminase antibodies in northwest of Iran

BACKGROUND:

High prevalence rates of celiac disease (CD) in patients with type-1 diabetes mellitus (T1DM) have been reported in several countries. However, the data regarding this association are scarce in Iran. In this study, we report the prevalence of CD in patients with T1DM in northwest of Iran using tissue transglutaminase antibodies (tTGA) as a screening test.

METHODOLOGY:

One hundred patients with T1DM (58 women and 42 men) aged 21.8 ± 8.86 years (age range: 7–50 years) were compared with 150 healthy people (82 women and 68 men) aged 28.9 ± 9.07 years (age range: 4–50 years). All subjects were serologically screened for the presence of tTGA. Total immunoglobin A (IgA) was obtained to investigate IgA deficiency. Subjects positive for tTGA and deficient for IgA were submitted to upper gastrointestinal endoscopy.

RESULTS:

Eight patients with T1DM (8%) and three of the controls (2%) were positive for tTGA (P = 0.023), while only 3% of the tTGA positive T1DM patients underwent duodenal biopsy and all of them showed partial or total villous atrophy. The mean age of tTGA positive cases was significantly lower than tTGA negative ones (mean difference 7.17; 95% CI: 0.82–13.52). None of the tTGA positive T1DM patients had a history of chronic diarrhea, but one out of eight tTGA positives reported history of dermatitis (P = 0.001). Also, none of the tTGA positive subjects presented IgA deficiency. There was a significant difference in history of chronic diarrhea (P = 0.006) and autoimmune diseases (P = 0.001) between patients with T1DM and controls.

CONCLUSION:

This study showed higher prevalence of CD in patients with T1DM than in general population of northwest Iran and the data lend support to recommend regular screening for CD in all patients with T1DM.

Ischemic colitis of the left colon in a diabetic patient

Diabetes mellitus may affect the gastrointestinal tract possibly as a result of autonomic neuropathy. Here we present a 68-year-old male with non-insulin-dependent diabetes mellitus who presented with prolonged watery diarrhea and in whom imaging studies demonstrated ischemic colitis of the left colon. Resection of the affected colon resulted in sustained disappearance of symptoms.

Diabetic diarrhea

Diabetic patients with diarrhea may present clinical challenges in diagnosis and treatment. Particular diagnoses are more prevalent in diabetic patients than in the general population. Medications are often a culprit for chronic diarrhea, and the medication list should always be carefully scrutinized for those with diarrhea as a side effect. In diabetic patients, metformin is a common cause of diarrhea. Diabetic patients are more likely to have associated diseases (eg, celiac sprue and microscopic colitis) that present with diarrhea as the sole complaint. Ingested sugar-free foods that may contain sorbitol or other agents can cause diarrhea in diabetic patients. Finally, diabetic enteropathy can itself cause diarrhea. The various etiologies can be diagnosed with a thorough history and appropriate diagnostic tests. This article focuses on the etiologies of diarrhea that are seen with higher incidence in diabetic patients.

Gain and loss of gastrointestinal symptoms in diabetes mellitus: associations with psychiatric disease, glycemic control, and autonomic neuropathy over 2 years of follow-up

OBJECTIVE

To prospectively determine the turnover (gain or loss) of gastrointestinal (GI) symptoms in diabetic subjects in relation to glycemic control, autonomic neuropathy and psychiatric disease over a 2-year follow-up.

METHODS

Type 1 and type 2 diabetic subjects were recruited from the community, as were community controls. Individual GI symptoms were examined by a validated questionnaire and classified as diarrhea, irritable bowel syndrome, upper GI symptoms, and any GI symptoms at baseline, 12 and 24 months. Glycemic control (glycated hemoglobin), autonomic function (using standardized tests), and psychiatric disease (using the Composite International Diagnostic Interview) were also assessed at these time points.

RESULTS

Baseline and 2-year follow-up data were available for 139 diabetic subjects and 55 controls. Glycated hemoglobin at baseline was 7.7% (+/-1.36) in the diabetic group; 5% had severe autonomic dysfunction. There was a significantly higher prevalence of diarrhea in the diabetic subjects. GI symptom turnover varied between 15% and 25% in the diabetic group and was not significantly different from the controls. There was no clear association between turnover of GI symptoms and either glycemic control or autonomic neuropathy. The appearance of depression was associated with gaining of most symptoms apart from irritable bowel syndrome, although the associations did not always reach significance. The univariate results were confirmed after adjusting for age, gender, body mass index, and metformin use.

CONCLUSION

The turnover of GI symptoms in diabetic subjects was not associated with glycemic control but there was a positive association with change in depression.

Medical therapy for diabetes is associated with increased use of lower endoscopy

BACKGROUND

Diabetes mellitus is associated with an increased risk of colorectal neoplasia and diabetes medications may further influence the risk. Observational studies of the effect of diabetes medications on colonic neoplasia may be biased if use of diabetes medications is associated with undergoing lower endoscopy. This study examined the association between diabetes therapies and use of lower endoscopy.

METHODS

This retrospective cohort study included patients with diabetes in an integrated, prepaid health plan. The primary exposure variables were use of sulfonylureas, metformin, thiazolidinediones (TZDs), and insulin. The outcome measure was completion of a flexible sigmoidoscopy or colonoscopy. Cox proportional hazards modeling, accounting for the time-varying nature of the medication exposures, was used to generate estimates of the relative hazard (HR) of lower endoscopy with different medications.

RESULTS

The study included 44 169 patients followed for a mean duration of 4.2 years (SD = 2.5 years); 34% underwent at least one lower endoscopy. Patients who filled a diabetes medication prescription were more likely to undergo lower endoscopy (HR = 1.13, 95%CI 1.06-1.21). Compared to those taking only sulfonylureas, patients receiving sulfonylureas and metformin (HR = 1.12, 95%CI 1.06-1.18) or metformin alone (HR = 1.17, 95%CI 1.07-1.26) were more likely to undergo lower endoscopy. For all medications, new use was associated with undergoing lower endoscopy (p < 0.05 for all comparisons).

CONCLUSIONS

Diabetic patients receiving medications are more likely to undergo lower endoscopy than those on diet control alone, particularly in the first year after initiating a new medication class and if taking metformin.

Autonomic Peripheral Neuropathy

Most generalized peripheral polyneuropathies are accompanied by clinical or subclinical autonomic dysfunction. There is a group of peripheral neuropathies in which the small or unmyelinated fibers are selectively targeted. In these neuropathies, autonomic dysfunction is the most prominent manifestation. The features associated with an autonomic neuropathy include impairment of cardiovascular, gastrointestinal, urogenital, thermoregulatory, sudomotor, and pupillomotor autonomic function.

Fecal incontinence in females older than aged 40 years: who is at risk?

PURPOSE

This study was designed to estimate the prevalence of, and identify risk factors associated with, fecal incontinence in racially diverse females older than aged 40 years.

METHODS

The Reproductive Risks for Incontinence Study at Kaiser is a population-based study of 2,109 randomly selected middle-aged and older females (average age, 56 years). Fecal incontinence, determined by self-report, was categorized by frequency. Females reported the level of bother of fecal incontinence and their general quality of life. Potential risk factors were assessed by self-report, interview, physical examination, and record review. Multivariate logistic regression analysis was used to determine the independent association between selected risk factors and the primary outcome of any reported fecal incontinence in the past year.

RESULTS

Fecal incontinence in the past year was reported by 24 percent of females (3.4 percent monthly, 1.9 percent weekly, and 0.2 percent daily). Greater frequency of fecal incontinence was associated with decreased quality of life (Medical Outcome Short Form-36 Mental Component Scale score, P = 0.01), and increased bother (P < 0.001) with 45 percent of females with fecal incontinence in the past year and 100 percent of females with daily fecal incontinence reporting moderate or great bother. In multivariate analysis, the prevalence of fecal incontinence in the past year increased significantly [odds ratio per 5 kg/m2 (95 percent confidence interval)] with obesity [1.2 (1.1-1.3)], chronic obstructive pulmonary disease [1.9 (1.3-2.9)], irritable bowel syndrome [2.4 (1.7-3.4)], urinary incontinence [2.1 (1.7-2.6)], and colectomy [1.9 (1.1-3.1)]. Latina females were less likely to report fecal incontinence than white females [0.6 (0.4-0.9)].

CONCLUSIONS

Fecal incontinence, a common problem for females, is associated with substantial adverse affects on quality of life. Several of the identified risk factors are preventable or modifiable, and may direct future research in fecal incontinence therapy.

Autonomic peripheral neuropathy

The autonomic neuropathies are a group of disorders in which the small, lightly myelinated and unmyelinated autonomic nerve fibres are selectively targeted. Autonomic features, which involve the cardiovascular, gastrointestinal, urogenital, sudomotor, and pupillomotor systems, occur in varying combination in these disorders. Diabetes is the most common cause of autonomic neuropathy in more developed countries. Autonomic neuropathies can also occur as a result of amyloid deposition, after acute infection, as part of a paraneoplastic syndrome, and after exposure to neurotoxins including therapeutic drugs. Certain antibodies (eg, anti-Hu and those directed against neuronal nicotinic acetylcholine receptor) are associated with autonomic signs and symptoms. There are several familial autonomic neuropathies with autosomal dominant, autosomal recessive, or X-linked patterns of inheritance. Autonomic dysfunction can occur in association with specific infections. The availability of sensitive and reproducible measures of autonomic function has improved physicians' ability to diagnose these disorders.

An overview of diarrhea in the patient receiving enteral nutrition

Many healthcare providers associate enteral tube feedings with diarrhea. Research suggests an incidence of diarrhea in patients receiving enteral tube feedings of 2% to 63%. This wide variation in incidence is due, in part, to the lack of a universal definition of diarrhea and other suspected factors that influence stool output such as malabsorption, infection, bacterial contamination of the feeding, medical diagnosis of the patient, medication therapy, or formula-related causes. An understanding of digestion, the role of fiber and fat in the diet, and the control for other influences will aid nurses in identifying interventions that promote a normal stool consistency in patients receiving enteral tube feedings. The need for further research regarding the causes and management of diarrhea is also supported.

Metformin as a cause of late-onset chronic diarrhea

Metformin is an effective and commonly administered drug for controlling plasma glucose concentrations in patients with type 2 diabetes mellitus. Gastrointestinal adverse effects such as abdominal pain, nausea, dyspepsia, anorexia, and diarrhea are common and widely accepted when occurring at the start of metformin therapy. Diarrhea occurring long after the dosage titration period is much less well recognized. Our patient began to experience nausea, abdominal cramping, and explosive watery diarrhea that occasionally caused incontinence after several years of stable metformin therapy A trial of metformin discontinuation resolved all gastrointestinal symptoms. A review of the literature revealed two reports that suggest diarrhea occurring long after the start of metformin therapy is relatively common, based on surveys of patients with diabetes. Metformin-induced diarrhea is differentiated from diabetic diarrhea, which is clinically similar, except diabetic diarrhea is rare in patients with type 2 diabetes. Patients with type 2 diabetes who are taking metformin and experience diarrhea deserve a drug-free interval before undergoing expensive and uncomfortable diagnostic tests, even when the dosage has been stable over a long period.

Insulin and IGF-I inhibit calcium-dependent chloride secretion by T84 human colonic epithelial cells

D-Myo-inositol (3,4,5,6) tetrakisphosphate [Ins(3,4,5,6)P(4)] or phosphatidylinositol 3-kinase (PI 3-kinase) activity acts to inhibit calcium-dependent chloride secretion in T84 colonic epithelial cells. To further distinguish between the contributions of these two signaling pathways to the inhibition of secretion, we studied effects of insulin, because the insulin receptor links to PI 3-kinase but not to pathways postulated to generate Ins(3,4,5,6)P(4). Chloride secretion across T84 cell monolayers was studied in Ussing chambers. Activation of PI 3-kinase was assessed by Western blotting. Basolateral, but not apical, addition of insulin inhibited carbachol- and thapsigargin-induced chloride secretion in a time- and concentration-dependent fashion. Insulin-like growth factor-I (IGF-I) had similar effects. Insulin had no effect on Ins(3,4,5,6)P(4) levels, and the inhibitory effects of insulin and IGF-I on chloride secretion were fully reversed by the PI 3-kinase inhibitors wortmannin and LY-294002. Western blot analysis showed that both insulin and IGF-I recruited the 85-kDa regulatory and 110-kDa catalytic subunits of PI 3-kinase to anti-phosphotyrosine immunoprecipitates. In conclusion, insulin and IGF-I act to inhibit calcium-dependent chloride secretion through a PI 3-kinase-dependent pathway. Because insulin is released in a pulsatile fashion postprandially and IGF-I levels are elevated in pathological settings, our findings may have physiological and/or pathophysiological significance.

Oral hypoglycaemic drugs and gastrointestinal symptoms in diabetes mellitus

BACKGROUND

Gastrointestinal symptoms are commonly reported as side-effects of oral hypoglycaemic drugs. It may be very difficult to distinguish between spontaneous and truly drug-related symptoms due to the high background incidence of gastrointestinal symptoms. Gastrointestinal symptoms in diabetic patients have also been linked to factors associated with long-standing disease and suboptimal control.

AIM

To explore the association between gastrointestinal symptoms and treatment with oral hypoglycaemic drugs in a large cohort of subjects with type 2 diabetes.

PATIENTS AND METHODS

956 subjects with type 2 diabetes participated in the study. All subjects completed a validated, self-administered questionnaire on gastrointestinal symptoms, diabetes, drug use and various potential risk factors for gastrointestinal symptoms. The association between oral hypoglycaemics and nine gastrointestinal symptom groups was assessed based on logistic regression.

RESULTS

405 of the 956 patients used oral hypoglycaemic drugs. Metformin use was independently associated with chronic diarrhoea (odds ratio 3.08, 95% CI: 1.29-7.36, P < 0.02) and with faecal incontinence (odds ratio 1.95, 95% CI: 1.10-3.47, P < 0.05). Use of sulphonylureas was associated with less abdominal pain, but not with any other gastrointestinal symptom.

CONCLUSIONS

Troublesome gastrointestinal symptoms do not appear to be caused by oral hypoglycaemics, except for diarrhoea and faecal incontinence, which are strongly and independently associated with metformin use.

Evaluating and Interpreting Epidemiological Risk

This special feature sets forth the basic skills pharmacists need to evaluate the primary literature with regard to epidemiological risk. The author discusses (1) the three key types of observational study designs used in epidemiological literature; (2) common measures of association and and their utility; (3) calculation of attributable risk, relative risk, and odds ratio; (4) the limitations of using relative risk and odds ratio; and (5) inappropriate use of risk in the primary literature.