Role of preoperative sarcopenia in predicting postoperative complications and survival after pancreatoduodenectomy for pancreatic cancer.

AIM: The aim of this monocentric retrospective study was to investigate the relation between sarcopenia, postoperative complications and survival in patients undergoing radical surgery for pancreatic ductal adenocarcinoma (PDAC). MATERIAL OF STUDY: From a prospective collected database of 230 consecutive pancreatoduodenectomies (PD), data regarding patient's body composition, evaluated on diagnostic preoperative CT scans and defined as Skeletal Muscle Index (SMI) and Intramuscular Adipose Tissue Content (IMAC), postoperative complications and long-term outcomes were retrospectively analysed. Descriptive and survival analyses were performed. RESULTS: Sarcopenia was found in 66% of study population. The majority of patients who developed at least one postoperative complication was sarcopenic. However, sarcopenia did not statistically significantly relate with the development of postoperative complications. However, all pancreatic fistula C occurs in sarcopenic patients. Moreover, there was no significant difference in median Overall Survival (OS) and Disease Free Survival (DFS) between sarcopenic and nonsarcopenic patients (31 versus 31.8 months and 12.9 and 11.1 months respectively). DISCUSSION: Our results showed that sarcopenia was not related to short- and long-term outcomes in PDAC patients undergoing PD. However, the quantitative and qualitative radiological parameters are probably not enough to study the sarcopenia alone. CONCLUSIONS: The majority of early stage PDAC patients undergoing PD were sarcopenic. Cancer stage was a determinant factor of sarcopenia while BMI seems less important. In our study, sarcopenia was associated with postoperative complications and in particular with pancreatic fistula. Further studies will need to demonstrated that sarcopenia can be considered an objective measure of patient frailty and strongly associated with short- and long-term outcomes. KEY WORDS: Pancreatic ductal adenocarcinoma, Pancretoduodenectomy, Sarcopenia.

Early impairment of food intake in patients newly diagnosed with cancer.

Background: Patients with gastrointestinal or lung cancer often suffer from a loss of appetite (anorexia), resulting in reduced food intake (hypophagia) and body weight loss. This study evaluated the prevalence of anorexia, hypophagia, pre-cachexia and cachexia in patients with cancer at time of diagnosis. Patients and methods: Patients with newly diagnosed gastrointestinal or lung cancers were included. Body mass index (BMI) and weight loss over the prior 6 months were recorded. Patients were assessed for (pre-)cachexia and for anorexia using the Functional Assessment of Anorexia/Cachexia Therapy (FAACT) and a specific anorexia questionnaire (AQ). Energy and protein intake were calculated through food diaries. Patients were considered hypophagic if intake was ≤70% of guideline-recommended levels. Results: Overall, 102 patients [53 male; median age: 67 (range, 21-88) years] were enrolled. Mean BMI (± standard deviation) was 23.1 ± 3.4 kg/m2; average percentage of weight loss was 10.1 ± 7.8%. At diagnosis, 68% (69/102) of patients had cachexia, and 11% (11/102) pre-cachexia. Prevalence of anorexia was 57% (58/102) and 75% (76/102) according to FAACT and AQ, respectively. Forty-eight percent (49/102) of patients had hypophagia. Patients with anorexia had lower daily energy (p = 0.002) and protein intake (p = 0.0257), and greater percentage of weight loss (p = 0.0005). In patients with hypophagia, negative correlations were observed between percentage of weight loss and total daily calorie (r = -0.40; p = 0.01) and protein intake (r = -0.340; p = 0.018). Conclusion: Anorexia, inadequate nutritional intake and cachexia are highly prevalent in patients with gastrointestinal or lung cancer at diagnosis. Negative protein and energy balance may play an important role in the pathogenesis of cachexia. Early multimodal strategies to improve food intake are urgently needed.

Diarrhea Predominant-Irritable Bowel Syndrome (IBS-D): Effects of Different Nutritional Patterns on Intestinal Dysbiosis and Symptoms.

Irritable Bowel Syndrome (IBS) is a chronic functional gastrointestinal disorder characterized by abdominal pain associated with defecation or a change in bowel habits. Gut microbiota, which acts as a real organ with well-defined functions, is in a mutualistic relationship with the host, harvesting additional energy and nutrients from the diet and protecting the host from pathogens; specific alterations in its composition seem to play a crucial role in IBS pathophysiology. It is well known that diet can significantly modulate the intestinal microbiota profile but it is less known how different nutritional approach effective in IBS patients, such as the low-FODMAP diet, could be responsible of intestinal microbiota changes, thus influencing the presence of gastrointestinal (GI) symptoms. The aim of this review was to explore the effects of different nutritional protocols (e.g., traditional nutritional advice, low-FODMAP diet, gluten-free diet, etc.) on IBS-D symptoms and on intestinal microbiota variations in both IBS-D patients and healthy subjects. To date, an ideal nutritional protocol does not exist for IBS-D patients but it seems crucial to consider the effect of the different nutritional approaches on the intestinal microbiota composition to better define an efficient strategy to manage this functional disorder.

Association between Dietary Habits and Fecal Microbiota Composition in Irritable Bowel Syndrome Patients: A Pilot Study.

Intestinal dysbiosis seems to play a role in the pathophysiology of irritable bowel syndrome (IBS). The present pilot study aimed to elucidate the association between nutrient intake and Mediterranean diet (MD) adherence with IBS symptoms and gut microbiota in IBS patients. The nutrient intake of 28 IBS patients and 21 controls was assessed through a food diary, the reference intake ranges (RIs) for energy-yielding macronutrients and the MD serving score (MDSS) index. MD adherence and nutrients intake were compared to IBS symptoms and fecal microbiota, obtained by 16S rRNA targeted-metagenomics. In IBS patients MDSS index was altered compared to controls (p < 0.01). IBS patients with low-MD score reported severe abdominal pain and higher flatulence point-scales. Through Linear discriminant analysis effect size (LEfSe), Erysipelotrichaceae were detected as a microbial biomarker in IBS patients with altered RIs for macronutrients intake, compared to controls. Lactobacillaceae and Lactobacillus were associated to an altered carbohydrates intake in IBS patients, while specific taxonomic biomarkers, such as Aldercreuzia, Mogibacteriaceae, Rikenellaceae, Parabacteroides and F. prausnitzii were associated with an adequate intake of nutrient in these patients. This study supports an association between dietary patterns and gut microbial biomarkers in IBS patients. Further investigations are needed to clarify these connections.

Impaired Colonic Contractility and Intestinal Permeability in Symptomatic Uncomplicated Diverticular Disease.

BACKGROUND/AIMS: Impaired intestinal motility seems to play a crucial role in symptomatic uncomplicated diverticular disease (SUDD), although the mechanism is not clear. The aim of the present study is to explore the contractility patterns of colonic smooth muscle strips (MS) and smooth muscle cells (SMCs) and to assess mucosal integrity in SUDD patients. METHODS: MS or SMCs were isolated from specimens of human distal colon of 18 patients undergoing surgery for non-obstructive colonic cancer, among them 9 with SUDD. Spontaneous phasic contractions on strips and morpho-functional parameters on cells were evaluated in basal conditions and in response to acetylcholine (ACh). Mucosal integrity of SUDD colonic biopsies was evaluated by the Ussing Chamber system. Immunohistochemical staining for tight junction protein complex and for Toll-like receptor 4 (TLR4) was performed. RESULTS: Colonic MS of SUDD group showed a significant reduced basal tone and ACh-elicited contraction, compared to the control group (9.5 g and 47.0% in the SUDD group; 14.16 g and 69.0% in the control group; P < 0.05). SMCs of SUDD group showed a maximal contractile response to ACh significantly reduced compared to control group (8.8% vs 16.5%, P < 0.05). SUDD patients displayed lower transepithelial electrical resistance and increased paracellular permeability compared to control group. Immunohistochemical expression of TLR4 was not different in both groups, while tight junction protein complex expression was lower in SUDD patients compared to control group patients. CONCLUSION: It could be hypothesized that in SUDD, in absence of severe inflammation, an increased intestinal mucosal permeability is related to altered colonic motility probably responsible for symptoms genesis.

Safety and tolerability of a novel oral nutritional supplement in healthy volunteers.

BACKGROUND AND OBJECTIVE: Foods for Special Medical Purposes (FSMPs) are formulated to support the nutritional needs of subjects with impaired capacity to ingest, digest or absorb ordinary food or nutrients. Polglumyt® is a proprietary highly purified, high quality glycogen obtained from mussels. Here we report the results of a single-center, single dose, open label, single arm study carried out to investigate acceptance (i.e. gastrointestinal tolerance and palatability), metabolic profile and safety of a low osmolarity, high-density energy Polglumyt®-based drink (the investigational product, IP) as a novel FSMP. METHODS: Twelve healthy subjects received a single oral administration of the IP under fasting conditions. The study endpoints were: changes in gastrointestinal system tolerability at 3 h, 6 h and 24 h after IP intake; IP palatability evaluation; metabolic evaluation through the kinetic profile of circulating glucose, insulin and C-peptide from 0 h to 6 h after IP intake and changes from baseline in circulating triglycerides at 3 h and 6 h after IP intake. RESULTS: The IP showed a good gastrointestinal tolerability and an acceptable palatability. The IP did not affect the physiological glycemic profile and the triglycerides levels 6 h after the intake. The IP was well tolerated by study subjects, with no or minor adverse events. CONCLUSIONS: The study results encourage additional clinical investigations on the IP as a novel FSMP in patients with impaired digestion or gastrointestinal absorption, unable to assume an ordinary diet, e.g. patients undergoing invasive gastrointestinal surgery, elderly or oncological patients, even with certain metabolic disorders.

Mechanisms of Action of Prebiotics and Their Effects on Gastro-Intestinal Disorders in Adults.

In recent years, research has focused on the use of dietary fibers and prebiotics, since many of these polysaccharides can be metabolized by intestinal microbiota, leading to the production of short-chain fatty acids. The metabolites of prebiotic fermentation also show anti-inflammatory and immunomodulatory capabilities, suggesting an interesting role in the treatment of several pathological conditions. Galacto-oligosaccharide and short- and long-chain fructans (Fructo-oligosaccharides and inulin) are the most studied prebiotics, even if other dietary compounds seem to show the same features. There is an increasing interest in dietary strategies to modulate microbiota. The aim of this review is to explore the mechanisms of action of prebiotics and their effects on the principal gastro-intestinal disorders in adults, with a special focus on Galacto-oligosaccharides, Fructo-oligosaccharides, lactulose and new emerging substances which currently have evidence of prebiotics effects, such as xilooligosaccharides, soybean oligosaccharides, isomaltooligosaccharides, lactobionic acid, resistant starch and polyphenols.

Nutritional Aspects in Inflammatory Bowel Diseases.

Crohn's disease (CD) and ulcerative colitis (UC) are chronic, relapsing, inflammatory disorders of the digestive tract that characteristically develop in adolescence and early adulthood. The reported prevalence of malnutrition in inflammatory bowel disease (IBD) patients ranges between 20% and 85%. Several factors, including reduced oral food intake, malabsorption, chronic blood and proteins loss, and intestinal bacterial overgrowth, contribute to malnutrition in IBD patients. Poor nutritional status, as well as selective malnutrition or sarcopenia, is associated with poor clinical outcomes, response to therapy and, therefore, quality of life. The nutritional assessment should include a dietetic evaluation with the assessment of daily caloric intake and energy expenditure, radiological assessment, and measurement of functional capacity.

Role of Overweight and Obesity in Gastrointestinal Disease.

The prevalence of obesity is increasing worldwide, leading to a severe impairment of overall health. Actually, obesity has been associated with several pathological conditions, causing an excess overall mortality. In particular, overweight and obesity are well known risk factors for a variety of gastrointestinal (GI) disorders i.e., functional GI disorders as well as, inflammatory bowel disease (IBD), pancreatitis, and GI cancer. The aim of the present review is to summarize the potential role of overweight and obesity in GI disease with particular focus on plausible biological mechanisms that could explain the association between obesity and GI disease based on the most recent evidence in the literature.

Nutritional status and bioelectrical phase angle assessment in adult Crohn disease patients receiving anti-TNFα therapy.

BACKGROUND: Altered body composition is frequently observed in Crohn's disease (CD) patients. AIMS: To investigate the nutritional status, and the effect of different therapeutic regimes in adult CD patients. METHODS: Fat free mass (FFM) and BIA-derived phase angle (PhA) were assessed in 45 CD patients, 22 on conventional therapy (CT) and 23 on maintenance therapy with infliximab (MT). Nutritional status was also assessed in 12 CD patients before and following the induction protocol with infliximab. BIA data of CD patients were compared with those of 20 healthy asymptomatic volunteers. In CD patients C Reactive Protein (CRP) and albuminaemia dosage were obtained. RESULTS: The mean values of PhA and of FFM were significantly lower in CT patients when compared with control group and MT patients. Following infliximab treatment FFM increased, although not significantly, while mean phase angle value significantly increased from 4.6±0.3 to 6.2±0.4 (p<0.05). CRP was significantly lower in MT patients compared to that in CT patients. CONCLUSION: CD patients on conventional therapy showed a lower FFM and a lower mean phase angle score compared to those on infliximab therapy. Following infliximab treatment the mean phase angle score normalized. PhA is a reliable nutritional indicator in IBD patients and could be considered as an additional tool for assessing response to treatment.

Role of Mixed Reflux and Hypomotility with Delayed Reflux Clearance in Patients with Non-cardiac Chest Pain.

BACKGROUND/AIMS: Gastroesophageal reflux disease (GERD) is the most common cause of non-cardiac chest pain (NCCP). Currently available data reveal a weak relationship between NCCP and dysmotility. Moreover, it is unclear why some refluxes are perceived as heartburn and others as NCCP. We aimed to evaluate the role of the reflux pattern and the esophageal motility in patients with NCCP. METHODS: Forty-eight patients with NCCP (Group 1) and 50 only typical GERD symptoms (Group 2) were included and underwent high-resolution manometry (HRM) and multichannel intraluminal impedance-pH monitoring. RESULTS: Impaired peristalsis was found in 60% of patients with NCCP and in 24% of patients with typical symptoms (P < 0.05). In patients belonging to Group 1, the majority of reflux episodes associated with chest pain were acid and mixed. The proportion of mixed refluxes was higher than that in Group 2. In Group 1, the reflux clearing time at 5, 9, and 15 cm, measured in reflux episodes associated to NCCP was longer than in reflux episodes associated to typical symptoms (mean ± 95% CI: 27.2 ± 5.6, 23.3 ± 4.4, and 14.6 ± 2.3 seconds vs 18.3 ± 3.5, 13.3 ± 2.2, and 11.1 ± 1.8 seconds; P < 0.01). CONCLUSIONS: The presence of gas in the refluxate seems to be associated with NCCP. The impaired motility observed in NCCP patients may play a relevant role in delaying reflux clearing, hence increasing the time of contact between refluxate and esophageal mucosa.

Weak peristalsis with large breaks is associated with higher acid exposure and delayed reflux clearance in the supine position in GERD patients.

OBJECTIVES: Ineffective esophageal motility is frequently observed in gastroesophageal reflux disease (GERD) patients but its clinical relevance remains controversial. In healthy subjects and in patients with nonobstructive dysphagia, it has been demonstrated, by means of high-resolution manometry (HRM), that long breaks of esophageal peristalsis predict delayed bolus clearance. METHODS: HRM and 24-h multichannel impedance-pH (MI-pH) monitoring were performed in 40 GERD patients with no evidence of hiatal hernia. Total bolus clearing time (BCT) in upright and supine position and acid exposure time (AET) were calculated. RESULTS: Of the 40 patients, 23 showed a pathological AET and 15 erosive reflux disease (ERD). Patients with a pathological number of large breaks were characterized by a significantly lower BCT value in the supine position and higher AET. In all, 10/15 ERD patients (67%) and 5/25 nonerosive reflux disease patients (20%) were characterized by an abnormal number of small or large breaks (P<0.05). ERD patients were characterized by significantly higher AET and BCT in the supine position. CONCLUSIONS: GERD patients with a pathological number of large breaks, assessed by HRM, are characterized by a significantly prolonged reflux clearance in the supine position and higher AET. ERD patients display a higher number of esophageal breaks that might explain the development of erosions.

Impedance-high resolution manometry analysis of patients with nonerosive reflux disease.

BACKGROUND & AIMS: Transient lower esophageal sphincter relaxations (TLESRs) contribute to episodes of reflux. Few studies have assessed the frequencies or compositions of TLESRs and reflux episodes in patients with reflux disease. We used combined high-resolution manometry and impedance monitoring to analyze reflux episodes and esophageal motility in these patients, compared with those of healthy individuals. METHODS: We evaluated the frequency of TLESRs and the relationship between the reflux pattern and esophageal pressures during TLESRs in 14 patients with nonerosive reflux disease (NERD) and 11 controls. Study participants underwent combined high-resolution manometry and impedance monitoring before and 60 minutes after a solid and liquid meal. The diagnosis of NERD was confirmed by a 24-hour pH impedance test. RESULTS: The frequency of TLESRs did not differ between patients with NERD and controls. In patients with NERD, TLESRs were associated more often with reflux episodes than in controls (93% ± 6% vs 66% ± 19%; P < .05). Patients with NERD had a higher percentage of pure liquid reflux episodes (33% ± 15% vs 10% ± 2%; P < .05), whereas controls had a higher percentage of mixed reflux episodes (45% ± 16% vs 67% ± 17% in patients with NERD; P < .05). Patients with NERD also had a higher percentage of reflux (liquid and mixed) associated with common cavities (74% ± 18% vs 50% ± 20% in controls; P < .05). CONCLUSIONS: In contrast to previous studies, we found that TLESRs are associated more often with reflux in patients with NERD than control subjects; this association increases when only liquid and mixed refluxes are considered. These findings indicate that factors involved in the occurrence of reflux in patients with NERD during TLESRs are different from those in healthy subjects.

Proton pump inhibitor resistance, the real challenge in gastro-esophageal reflux disease.

Gastro-esophageal reflux disease (GERD) is one of the most prevalent chronic diseases. Although proton pump inhibitors (PPIs) represent the mainstay of treatment both for healing erosive esophagitis and for symptom relief, several studies have shown that up to 40% of GERD patients reported either partial or complete lack of response of their symptoms to a standard PPI dose once daily. Several mechanisms have been proposed as involved in PPIs resistance, including ineffective control of gastric acid secretion, esophageal hypersensitivity, ultrastructural and functional changes in the esophageal epithelium. The diagnostic evaluation of a refractory GERD patients should include an accurate clinical evaluation, upper endoscopy, esophageal manometry and ambulatory pH-impedance monitoring, which allows to discriminate non-erosive reflux disease patients from those presenting esophageal hypersensitivity or functional heartburn. Treatment has been primarily based on doubling the PPI dose or switching to another PPI. Patients with proven disease, not responding to PPI twice daily, are eligible for anti-reflux surgery.

Gastro-esophageal reflux disease and obesity, where is the link?

The confluence between the increased prevalence of gastro-esophageal reflux disease (GERD) and of obesity has generated great interest in the association between these two conditions. Several studies have addressed the potential relationship between GERD and obesity, but the exact mechanism by which obesity causes reflux disease still remains to be clearly defined. A commonly suggested pathogenetic pathway is the increased abdominal pressure which relaxes the lower esophageal sphincter, thus exposing the esophageal mucosal to gastric content. Apart from the mechanical pressure, visceral fat is metabolically active and it has been strongly associated with serum levels of adipo-cytokines including interleukin-6 and tumor necrosis factor α, which may play a role in GERD or consequent carcinogenesis. This summary is aimed to explore the potential mechanisms responsible for the association between GERD and obesity, and to better understand the possible role of weight loss as a therapeutic approach for GERD.

Gastroesophageal reflux disease: Update on inflammation and symptom perception.

Although gastroesophageal reflux disease (GERD) is a common disorder in Western countries, with a significant impact on quality of life and healthcare costs, the mechanisms involved in the pathogenesis of symptoms remain to be fully elucidated. GERD symptoms and complications may result from a multifactorial mechanism, in which acid and acid-pepsin are the important noxious factors involved. Prolonged contact of the esophageal mucosa with the refluxed content, probably caused by a defective anti-reflux barrier and luminal clearance mechanisms, would appear to be responsible for macroscopically detectable injury to the esophageal squamous epithelium. Receptors on acid-sensitive nerve endings may play a role in nociception and esophageal sensitivity, as suggested in animal models of chronic acid exposure. Meanwhile, specific cytokine and chemokine profiles would appear to underlie the various esophageal phenotypes of GERD, explaining, in part, the genesis of esophagitis in a subset of patients. Despite these findings, which show a significant production of inflammatory mediators and neurotransmitters in the pathogenesis of GERD, the relationship between the hypersensitivity and esophageal inflammation is not clear. Moreover, the large majority of GERD patients (up to 70%) do not develop esophageal erosions, a variant of the condition called non-erosive reflux disease. This summary aims to explore the inflammatory pathway involved in GERD pathogenesis, to better understand the possible distinction between erosive and non-erosive reflux disease patients and to provide new therapeutic approaches.

Ursodeoxycholic acid therapy in gallbladder disease, a story not yet completed.

Gallstone disease represents an important issue in the healthcare system. The principal non-invasive non-surgical medical treatment for cholesterol gallstones is still represented by oral litholysis with bile acids. The first successful and documented dissolution of cholesterol gallstones was achieved in 1972. Since then a large number of investigators all over the world, have been dedicated in biochemical and clinical studies on ursodeoxycholic acid (UDCA), demonstrating its extreme versatility. This editorial is aimed to provide a brief review of recent developments in UDCA use, current indications for its use and, the more recent advances in understanding its effects in terms of an anti-inflammatory drug.

Human colonic myogenic dysfunction induced by mucosal lipopolysaccharide translocation and oxidative stress.

BACKGROUND: Impairment of gastrointestinal motility is frequently observed in patients with severe infection. AIM: To assess whether exposure of human colonic mucosa to pathogenic lipopolysaccharide affects smooth muscle contractility. METHODS: Human colonic mucosa and submucosa were sealed between two chambers, with the luminal side facing upwards and covered with Krebs solution, with or without lipopolysaccharide from a pathogenic strain of Escherichia coli (O111:B4; 1,000 ng/mL), and with the submucosal side facing downwards into Krebs. The solution on the submucosal side was collected following 30-min mucosal exposure to Krebs without (N-undernatant) or with lipopolysaccharide (lipopolysaccharide undernatant). Undernatants were tested for lipopolysaccharide and hydrogen peroxide levels and for their effects on smooth muscle cells in the presence of catalase, indomethacin or MG132. RESULTS: Smooth muscle cells incubated with N-undernatant had a maximal contraction of 32 ± 5% that was reduced by 62.9 ± 12% when exposed to lipopolysaccharide undernatant. Inhibition of contraction was reversed by catalase, indomethacin and MG132. Lipopolysaccharide levels were higher in the lipopolysaccharide undernatant (2.7 ± 0.7 ng/mL) than in N-undernatant (0.45 ± 0.06 ng/mL) as well as hydrogen peroxide levels (133.75 ± 15.9 vs 82 ± 7.5 nM respectively). CONCLUSIONS: Acute exposure of colonic mucosa to pathogenic lipopolysaccharide impairs muscle cell contractility owing to both lipopolysaccharide mucosal translocation and production of free radicals.

Impedance baseline and reflux perception in responder and non-responder non-erosive reflux disease patients.

BACKGROUND: It was recently shown that GERD patients have lower impedance baseline (IB) values than healthy controls and, that the esophageal acid exposure time (AET) correlates with IB levels. GOALS: To explore the sensitivity of IB measurements in NERD patients, responders and non-responders to PPIs, when compared with pH-impedance (MII-pH) variables, and to evaluate whether this variable could represent a marker of GERD symptoms. Reproducibility and inter-observer agreement of IB measurement were also assessed. Study. MII-pH tracings from 44 NERD responders and 22 non-responders were analysed. Ten healthy volunteers underwent the same protocol. IB values were measured at the distal and proximal esophagus. IB was also analysed in a subgroup of patients and in controls with two methods and by two blinded operators. RESULTS: Mean IB values at the distal esophagus were significantly lower in NERD patients than in controls. IB values did not differ between responders and non-responders. Of the 8 responders with negative AET and symptom association probability (SAP), 3 (37.5%) showed IB values lower than controls. IB values in responders with positive and negative SAP were similar (1832 (1596-2068) Ω vs 1667 (1361-1973) Ω, p: n.s.). No differences were found between the IB values measured with the two methods and the inter-observer agreement was good. CONCLUSIONS: IB is a promising and easy to calculate MII-pH variable and appears to increase the sensitivity of MII-pH monitoring. IB values cannot predict PPI response and are not associated with reflux perception in NERD patients.

Increased frequency and enhanced perception of reflux in non-erosive reflux disease patients non-responders to proton pump inhibitors.

BACKGROUND: The unsatisfactory response to medical treatment in non-erosive patients is becoming a real challenge for gastroenterologists. Non-responder patients, evaluated under treatment, present symptoms which are related to non-acidic, mixed and proximal reflux episodes. METHODS: To elucidate the reflux pattern and mechanisms related to persistence of symptoms despite treatment, oesophageal pH-impedance was performed in 55 non-erosive responder and 24 non-responder patients, studied off therapy. Ten responder and 10 non-responder patients underwent a repeated study during proton pump inhibitor treatment. RESULTS: Non-responders were characterised by a higher overall number and larger proportion of symptomatic reflux episodes. Non-responders were also characterised by an enhanced sensitivity to acidic, mixed and proximal refluxes. Weakly acidic reflux accounted for 29% of symptomatic refluxes in non-responders and 34% in responders. Proportions of acidic and weakly acidic reflux episodes were comparable both in responders and non-responders when analysed off and on treatment. CONCLUSIONS: An increased overall number of reflux episodes and enhanced sensitivity to reflux are strongly associated with treatment failure. Treatment strategies aimed at decreasing transient lower oesophageal sphincter relaxations, pain modulators or anti-reflux surgery should be considered in non-responders in whom a significant relationship between symptoms and reflux has been confirmed.