Development of a Core Outcome Set for Children Aged 1-18 Years with Gastroesophageal Reflux Disease.

OBJECTIVE: To develop a core outcome set for clinical studies assessing gastroesophageal reflux disease (GERD) in children. STUDY DESIGN: This core outcome set was developed using a 2-round Delphi technique and adhering to the Outcome Measures in Rheumatology Initiative (OMERACT 2.0) recommendations. Healthcare professionals (HCPs) and (parents of) children (age 1-18 years) with a GERD diagnosis (ie, the presence of bothersome symptoms), listed up to 5 harmful and/or beneficial outcomes that they considered important in the treatment of GERD. Outcomes mentioned by more than 10% of participants were put forward and rated and prioritized by HCPs, parents, and children in a second round. Outcomes with the highest rank formed the draft core outcome set. The final core outcome set was created during an online consensus meeting between an expert panel. RESULTS: The first round was completed by 118 of 125 HCPs (94%), 146 of 146 parents (100%), and 69 of 70 children (99%). A total of 80 of 118 HCPs (68%), 130 of 140 parents (93%), and 77 children (100%) completed round 2. "Adequate relief," "evidence of esophagitis," "feeding difficulties," "heartburn (≥4 years)," "hematemesis," "regurgitation," "sleeping difficulties," "vomiting," and "adverse events" were included in the final core outcome set for GERD in children aged 1-18 years. CONCLUSIONS: We identified a total set of 9 core outcomes and suggest these outcomes to be minimally measured in clinical studies assessing GERD in children. Implementation of this core outcome set is likely to increase comparison between studies and may thus provide future recommendations to improve treatment of GERD in children.

Clinical Experience With Performing Esophageal Function Testing in Children.

OBJECTIVES: Pediatric high-resolution manometry (HRM) and 24-hour pH-impedance with/without ambulatory manometry (pH-MII+/-mano) tests are generally performed using adult-derived protocols. We aimed to assess the feasibility of these protocols in children, the occurrence of patient-related imperfections and their influence on test interpretability. METHODS: Esophageal function tests performed between 2015 and 2018 were retrospectively analyzed. All tests were subcategorized into uninterpretable or interpretable tests (regardless of occurrence of patient-related imperfections). For HRM, the following patient-related imperfections were scored: patient-related artefacts, multiple swallowing and/or inability to establish baseline characteristics. For pH-MII(+/-mano), incorrect symptom registration and/or premature catheter removal were scored. Results were compared between age-groups (0-3, 4-12, and >12 years). RESULTS: In total 106 HRM, 60 pH-MII, and 23 pH-MII-mano could be fully analyzed. Of these, 94.8% HRM, 91.9% pH-MII, and 95.7% pH-MII-mano were interpretable. Overall, HRM contained imperfections in 78.3% overall and in 8/8 (100%) in the youngest age group, 36/42 (85.7%) in 4 to 12 years and in 37/56 (66.1%) in children above 12 years; P = 0.011. These imperfections led to uninterpretable results in 4 HRM (3.8%), of which 3 were in the youngest age group (3/8, 37.5%). Imperfections were found in 10% of pH-MII and 17.4% of pH-MII-mano. These led to uninterpretable results in 5.0% and 4.3%, respectively. No age-effect was found. CONCLUSIONS: Esophageal function tests in children are interpretable in more than 90% overall. In children under the age of 4 years, all patients had imperfect HRM and 3/8 tests were uninterpretable. HRM in older children and pH-MII+/-mano were interpretable in the vast majority.

Neonatal microbiota development and the effect of early life antibiotics are determined by two distinct settler types.

The neonatal period, during which the initial gut microbiota is acquired, is a critical phase. The healthy development of the infant's microbiome can be interrupted by external perturbations, like antibiotics, which are associated with profound effects on the gut microbiome and various disorders later in life. The aim of this study was to investigate the development of intestinal microbiota and the effect of antibiotic exposure during the first three months of life in term infants. Fecal samples were collected from healthy infants and infants who received antibiotics in the first week of life at one week, one month, and three months after birth. Microbial composition was analyzed using IS-pro and compared between antibiotics-treated and untreated infants. In total, 98 infants, divided into four groups based on feeding type and delivery mode, were analyzed. At one week of age, samples clustered into two distinct groups, which were termed "settler types", based on their Bacteroidetes abundance. Caesarean-born infants belonged to the low-Bacteroidetes settler type, but vaginally-born infants were divided between the two groups. The antibiotics effect was assessed within a subgroup of 45 infants, vaginally-born and exclusively breastfed, to minimize the effect of other confounders. Antibiotics administration resulted in lower Bacteroidetes diversity and/or a delay in Bacteroidetes colonization, which persisted for three months, and in a differential development of the microbiota. Antibiotics resulted in pronounced effects on the Bacteroidetes composition and dynamics. Finally, we hypothesize that stratification of children's cohorts based on settler types may reveal group effects that might otherwise be masked.

High-resolution esophageal manometry in pediatrics: Effect of esophageal length on diagnostic measures.

BACKGROUND: High-resolution esophageal manometry (HREM), derived esophageal pressure topography metrics (EPT), integrated relaxation pressure (IRP), and distal latency (DL) are influenced by age and size. Combined pressure and intraluminal impedance also allow derivation of metrics that define distension pressure and bolus flow timing. We prospectively investigated the effects of esophageal length on these metrics to determine whether adjustment strategies are required for children. METHODS: Fifty-five children (12.3 ± 4.5 years) referred for HREM, and 30 healthy adult volunteers (46.9 ± 3.8 years) were included. Studies were performed using the MMS system and a standardized protocol including 10 × 5 mL thin liquid bolus swallows (SBM kit, Trisco Foods) and analyzed via Swallow Gateway (www.swallowgateway.com). Esophageal distension pressures and swallow latencies were determined in addition to EGJ resting pressure and standard EPT metrics. Effects of esophageal length were examined using partial correlation, correcting for age. Adult-derived upper limits were adjusted for length using the slopes of the identified linear equations. KEY RESULTS: Mean esophageal length in children was 16.8 ± 2.8 cm and correlated significantly with age (r = 0.787, P = .000). Shorter length correlated with higher EGJ resting pressure and 4-s integrated relaxation pressures (IRP), distension pressures, and shorter contraction latencies. Ten patients had an IRP above the adult upper limit. Adjustment for esophageal length reduced the number of patients with elevated IRP to three. CONCLUSIONS & INFERENCES: We prospectively confirmed that certain EPT metrics, as well as potential useful adjunct pressure-impedance measures such as distension pressure, are substantially influenced by esophageal length and require adjusted diagnostic thresholds specifically for children.

Definitions of Pediatric Functional Abdominal Pain Disorders and Outcome Measures: A Systematic Review.

OBJECTIVE: To systematically review definitions of functional abdominal pain orders (FAPDs) and outcome measures used in therapeutic randomized controlled trials in pediatric FAPDs adhering to the Outcome Measures in Rheumatology recommendations. STUDY DESIGN: Cochrane, MEDLINE, Embase, and Cinahl databases were systematically searched from inception to April 2018. English-written therapeutic randomized controlled trials concerning FAPDs in children aged 4-18 years were included. Definitions of FAPDs, interventions, outcome measures, measurement instruments, and outcome assessors of each study were tabulated descriptively. Quality was assessed using the Delphi List. RESULTS: A total of 4771 articles were found, of which 64 articles were included (n = 25, 39% of high methodologic quality). The Rome III (50%), Rome II (17%), Apley (16%), and author-defined (17%) criteria were used to define FAPDs. Fourteen studies (22%) assessed a pharmacologic, 25 (39%) a dietary, and 25 (39%) a psychosocial intervention. Forty-four studies (69%) predefined their primary outcomes. In total, 211 reported predefined outcome measures were grouped into 23 different outcome domains; the majority being patient-reported (n = 27, 61%). Of the 14 studies that evaluated a pharmacologic intervention, 12 (86%) reported on adverse events. CONCLUSIONS: Studies on pediatric FAPDs are of limited methodologic quality and show large heterogeneity and inconsistency in defining FAPDs and outcome measures used. Development of a core outcome set is needed to make comparison between intervention studies possible.

Oesophageal atresia.

Oesophageal atresia (EA) is a congenital abnormality of the oesophagus that is caused by incomplete embryonic compartmentalization of the foregut. EA commonly occurs with a tracheo-oesophageal fistula (TEF). Associated birth defects or anomalies, such as VACTERL association, trisomy 18 or 21 and CHARGE syndrome, occur in the majority of patients born with EA. Although several studies have revealed signalling pathways and genes potentially involved in the development of EA, our understanding of the pathophysiology of EA lags behind the improvements in surgical and clinical care of patients born with this anomaly. EA is treated surgically to restore the oesophageal interruption and, if present, ligate and divide the TEF. Survival is now ~90% in those born with EA with severe associated anomalies and even higher in those born with EA alone. Despite these achievements, long-term gastrointestinal and respiratory complications and comorbidities in patients born with EA are common and lead to decreased quality of life. Oesophageal motility disorders are probably ubiquitous in patients after undergoing EA repair and often underlie these complications and comorbidities. The implementation of several new diagnostic and screening tools in clinical care, including high-resolution impedance manometry, pH-multichannel intraluminal impedance testing and disease-specific quality of life questionnaires now provide better insight into these problems and may contribute to better long-term outcomes in the future.

Development of a Core Outcome Set for Infant Gastroesophageal Reflux Disease.

OBJECTIVE: In therapeutic trials for infant gastroesophageal reflux disease (GERD), ways to define GERD and measure and report study outcomes vary widely. The aim of this study was to develop a core outcome set (COS) for infant GERD. METHODS: The COS was developed using the Delphi technique, adhering to the Outcome Measures in Rheumatology Initiative 2.0 recommendations. Healthcare professionals (HCPs) (predominantly pediatric gastroenterologists and general pediatricians) and parents of infants (age 0-12 months) with GERD, listed up to 5 primary goals of therapy from their perspective and up to 5 persistent signs or symptoms that would signify inadequate treatment. Outcomes mentioned by >10% of participants were included in 2 shortlists. Next, HCPs and parents rated and prioritized outcomes on these shortlists. Outcomes with the highest rank formed the draft COS. The final COS was created after 2 consensus meetings between an expert panel and patient representatives. RESULTS: In total, 125 of 165 HCPs (76%) and 139 of 143 parents (97%) of infants with GERD completed the first phase. The second phase was completed by 83 of 139 HCPs (60%) and 127 of 142 different parents (89%). Outcomes of these phases were discussed during the consensus meetings and a 9-item COS was formed: "Adequate Growth," "Adequate Relief," "Adverse events,", "Crying," "Evidence of Esophagitis," "Feeding Difficulties," "Hematemesis," "No Escalation of Therapy," and "Sleep Problems." CONCLUSIONS: We developed a COS for infant GERD consisting of 9 items that should minimally be measured in future therapeutic trials to decrease study heterogeneity and ease comparability of results.

Measurement of Salivary Pepsin to Detect Gastroesophageal Reflux Disease Is Not Ready for Clinical Application.

A noninvasive test for gastroesophageal reflux disease (GERD) is desirable for adults and children. Salivary pepsin measurement has been proposed as such a test.1-3 A previous study from our group demonstrated that a maximal salivary pepsin cutoff of >210 ng/mL using the PepTest device (RD Biomed, Hull, United Kingdom) had excellent specificity of 96% but modest sensitivity of 44% to diagnose GERD,4 leading to optimism about its potential use. In this study, we aimed to confirm the previously reported sensitivity and specificity in healthy volunteers and patients with heartburn, evaluate the association between a positive PepTest and response to proton pump inhibitor (PPI) therapy, assess if test-sensitivity can be improved for GERD when samples are taken over a 72-hour sampling period, and establish normal values of salivary pepsin in infants.

Clinical Management of Pediatric Achalasia: A Survey of Current Practice.

OBJECTIVES: Pediatric achalasia is a rare neurodegenerative disorder of the esophagus that requires treatment. Different diagnostic and treatment modalities are available, but there are no data that show how children can best be diagnosed and treated. We aimed to identify current practices regarding the diagnostic and therapeutic approach toward children with achalasia. METHODS: Information on the current practice regarding the management of pediatric achalasia was collected by an online-based survey sent to members of the European and North American Societies for Pediatric Gastroenterology Hepatology and Nutrition involved in pediatric achalasia care. RESULTS: The survey was completed by 38 centers from 24 countries. Within these centers, 108 children were diagnosed with achalasia in the last year (median 2, range 0-15). Achalasia was primarily managed by a pediatric gastroenterologist (76%) and involved a multidisciplinary team in 84% of centers, also including a surgeon (87%), radiologist (61%), dietician (37%), speech pathologist (8%), and psychologist (5%). Medical history taking and physical examination were considered most important to establish the diagnosis (50%), followed by (a combination of) manometry (45%) or contrast swallow (21%). Treatment of first choice was Heller myotomy (58%), followed by pneumatic dilation (46%) and peroral endoscopic myotomy (29%). CONCLUSION: This study shows a great heterogeneity in the management of pediatric achalasia amongst different centers worldwide. These findings stress the need for well-designed intervention trials in children with achalasia. Given the rarity of this disease, we recommend that achalasia care should be managed in centers with access to appropriate diagnostic and treatment modalities.

Clinical management of pediatric achalasia.

INTRODUCTION: Achalasia is a rare esophageal motility disorder. Much of the literature is based on the adult population. In adults, guidance of therapeutic approach by manometric findings has led to improvement in patient outcome. Promising results have been achieved with novel therapies such as PerOral Endoscopic Myotomy (POEM). Areas covered: In this review, we provide an overview of the novel diagnostic and therapeutic tools for achalasia management and in what way they will relate to the future management of pediatric achalasia. We performed a PubMed and EMBASE search of English literature on achalasia using the keywords 'children', 'achalasia', 'pneumatic dilation', 'myotomy' and 'POEM'. Cohort studies < 10 cases and studies describing patients ≥ 20 years were excluded. Data regarding patient characteristics, treatment outcome and adverse events were extracted and presented descriptively, or pooled when possible. Expert commentary: Available data report that pneumatic dilation and laparoscopic Heller's myotomy are effective in children, with certain studies suggesting lower success rates in pneumatic dilation. POEM is increasingly used in the pediatric setting with promising short-term results. Gastro-esophageal reflux disease (GERD) may occur post-achalasia intervention due to disruption of the LES and therefore requires diligent follow-up, especially in children treated with POEM.

Pediatric Gastroesophageal Reflux Disease: Systematic Review on Prognosis and Prognostic Factors.

In this systematic review, we summarize the evidence on prognosis and prognostic factors of pediatric gastroesophageal reflux disease (GERD). A structured search of Embase and MEDLINE/PubMed (inception to April 2016) yielded 5365 references; 4 publications met our inclusion criteria (risk of bias moderate-high). Definitions and outcome measures varied widely between studies. The percentage of children with a diagnosis of GERD with esophagitis that had persisting symptoms and/or were on antireflux medication at follow-up (12 months to >5 years) ranged from 23% (weekly symptoms) to 68% (antireflux medication), depending on definition used. In children with a diagnosis of GERD without esophagitis, 1.4% developed esophagitis at follow-up (>5 years); none developed Barrett esophagus. In conclusion, prognostic studies on pediatric GERD are of limited quality and show large methodological heterogeneity. Based on these studies, we are unable to identify those children at risk for unfavorable outcome with regards to GERD symptoms or endoscopic complications.

Novel Pressure-Impedance Parameters for Evaluating Esophageal Function in Pediatric Achalasia.

OBJECTIVE: In achalasia, absent peristalsis and reduced esophagogastric junction (EGJ) relaxation and compliance underlie dysphagia symptoms. Novel high-resolution impedance manometry variables, that is, bolus presence time (BPT) and trans-EGJ-bolus flow time (BFT) have been developed to estimate the duration of EGJ opening and trans-EGJ bolus flow. The aim of this study was to evaluate esophageal motor function and bolus flow in children diagnosed with achalasia using these variables. METHODS: High-resolution impedance manometry recordings from 20 children who fulfilled the Chicago Classification (V3) criteria for achalasia were compared with recordings of 15 children with normal esophageal high-resolution manometry findings and no other evidence suggestive of achalasia. Matlab-based analysis software was used to calculate BPT and BFT. RESULTS: Both BPT and BFT were significantly reduced in achalasia patients compared with children with normal esophageal motility (BPT 3.3 s vs 5.1 s P < 0.01; BFT 1.4 s vs 4.3 s P < 0.001). BFT was significantly lower than BPT (achalasia difference 1.9 s ±â€Š1.3 s, P = 0.001 and normal difference 0.9 ±â€Š0.3 s, P = 0.001). Overall, there was a significant correlation between BPT and BFT (r = 0.825, P < 0.001). We observed a 2-way differentiation of achalasia patients; those in whom the BPT and BFT were proportional, but significantly lower than in patients with normal peristalsis, and those in whom BFT was disproportionately lower than BPT. CONCLUSIONS: Calculation of BPT and BFT may help determine whether esophageal bolus transport to the EGJ and/or esophageal emptying through the EGJ are aberrant. For achalasia, this may detect flow resistance at the EGJ, potentially improving both diagnosis and objective assessment of therapeutic effects.

Variations in Definitions and Outcome Measures in Gastroesophageal Reflux Disease: A Systematic Review.

CONTEXT: Gastroesophageal reflux (GER) is defined as GER disease (GERD) when it leads to troublesome symptoms and/or complications. We hypothesized that definitions and outcome measures in randomized controlled trials (RCTs) on pediatric GERD would be heterogeneous. OBJECTIVES: Systematically assess definitions and outcome measures in RCTs in this population. DATA SOURCES: Data were obtained through Cochrane, Embase, Medline, and Pubmed databases. STUDY SELECTION: We selected English-written therapeutic RCTs concerning GERD in children 0 to 18 years old. DATA EXTRACTION: Data were tabulated and presented descriptively. Each individual parameter or set of parameters with unique criteria for interpretation was considered a single definition for GER(D). Quality was assessed by using the Delphi score. RESULTS: A total of 2410 unique articles were found; 46 articles were included. Twenty-six (57%) studies defined GER by using 25 different definitions and investigated 25 different interventions. GERD was defined in 21 (46%) studies, all using a unique definition and investigating a total of 23 interventions. Respectively 87 and 61 different primary outcome measures were reported by the studies in GER and GERD. Eight (17%) studies did not report on side effects. Of the remaining 38 (83%) studies that did report on side effects, 18 (47%) included this as predefined outcome measure of which 4 (22%) as a primary outcome measure. Sixteen studies (35%) were of good methodological quality. LIMITATIONS: Only English-written studies were included. CONCLUSIONS: Inconsistency and heterogeneity exist in definitions and outcome measures used in RCTs on pediatric GER and GERD; therefore, we recommend the development of a core outcome set.

Reliability of the reflux finding score for infants in flexible versus rigid laryngoscopy.

OBJECTIVES: The Reflux Finding Score for Infants (RFS-I) was developed to assess signs of laryngopharyngeal reflux (LPR) in infants. With flexible laryngoscopy, moderate inter- and highly variable intraobserver reliability was found. We hypothesized that the use of rigid laryngoscopy would increase reliability and therefore evaluated the reliability of the RFS-I for flexible versus rigid laryngoscopy in infants. METHODS: We established a set of videos of consecutively performed flexible and rigid laryngoscopies in infants. The RFS-I was scored twice by 4 otorhinolaryngologists, 2 otorhinolaryngology fellows, and 2 inexperienced observers. Cohen's and Fleiss' kappas (k) were calculated for categorical data and the intraclass correlation coefficient (ICC) was calculated for ordinal data. RESULTS: The study set consisted of laryngoscopic videos of 30 infants (median age 7.5 (0-19.8) months). Overall interobserver reliability of the RFS-I was moderate for both flexible (ICC = 0.60, 95% CI 0.44-0.76) and rigid (ICC = 0.42, 95% CI 0.26-0.62) laryngoscopy. There were no significant differences in reliability of overall RFS-I scores and individual RFS-I items for flexible versus rigid laryngoscopy. Intraobserver reliability of the total RFS-I score ranged from fair to excellent for both flexible (ICC = 0.33-0.93) and rigid (ICC = 0.39-0.86) laryngoscopies. Comparing RFS-I results for flexible versus rigid laryngoscopy per observer, reliability ranged from no to substantial (k = -0.16-0.63, mean k = 0.22), with an observed agreement of 0.08-0.35. CONCLUSION: Reliability of the RFS-I was moderate and did not differ between flexible and rigid laryngoscopies. The RFS-I is not suitable to detect signs or to guide treatment of LPR in infants, neither with flexible nor with rigid laryngoscopy.

Pressure-flow characteristics of normal and disordered esophageal motor patterns.

OBJECTIVE: To perform pressure-flow analysis (PFA) in a cohort of pediatric patients who were referred for diagnostic manometric investigation. STUDY DESIGN: PFA was performed using purpose designed Matlab-based software. The pressure-flow index (PFI), a composite measure of bolus pressurization relative to flow and the impedance ratio, a measure of the extent of bolus clearance failure were calculated. RESULTS: Tracings of 76 pediatric patients (32 males; 9.1 ± 0.7 years) and 25 healthy adult controls (7 males; 36.1 ± 2.2 years) were analyzed. Patients mostly had normal motility (50%) or a category 4 disorder and usually weak peristalsis (31.5%) according to the Chicago Classification. PFA of healthy controls defined reference ranges for PFI ≤142 and impedance ratio ≤0.49. Pediatric patients with pressure-flow (PF) characteristics within these limits had normal motility (62%), most patients with PF characteristics outside these limits also had an abnormal Chicago Classification (61%). Patients with high PFI and disordered motor patterns all had esophagogastric junction outflow obstruction. CONCLUSIONS: Disordered PF characteristics are associated with disordered esophageal motor patterns. By defining the degree of over-pressurization and/or extent of clearance failure, PFA may be a useful adjunct to esophageal pressure topography-based classification.

Development of the reflux finding score for infants and its observer agreement.

OBJECTIVE: It is hypothesized that laryngeal edema is caused by laryngopharyngeal reflux (LPR) (ie, gastroesophageal reflux extending into the larynx and pharynx). The validated reflux finding score (RFS) assesses LPR disease in adults. We, therefore, aimed to develop an adapted RFS for infants (RFS-I) and assess its observer agreement. STUDY DESIGN: Visibility of laryngeal anatomic landmarks was assessed by determining observer agreement. The RFS-I was developed based on the RFS, the found observer agreement, and expert opinion. An educational tutorial was developed which was presented to 3 pediatric otorhinolaryngologists, 2 otorhinolaryngologists, and 2 gastroenterology fellows. They then scored videos of flexible laryngoscopy procedures of infants who were either diagnosed with or specifically without laryngeal edema. RESULTS: In total, 52 infants were included with a median age of 19.5 (0-70) weeks, with 12 and 40 infants, respectively, for the assessment of the laryngeal anatomic landmarks and the assessment of the RFS-I. Overall interobserver agreement of the RFS-I was moderate (intraclass correlation coefficient = 0.45). Intraobserver agreement ranged from moderate to excellent agreement (intraclass correlation coefficient = 0.50-0.87). CONCLUSION: A standardized scoring instrument was developed for the diagnosis of LPR disease using flexible laryngoscopy. Using this tool, only moderate interobserver agreement was reached with a highly variable intraobserver agreement. Because a valid scoring system for flexible laryngoscopy is lacking up until now, the RFS-I and flexible laryngoscopy should not be used solely to clinically assess LPR related findings of the larynx, nor to guide treatment.

Upper gastrointestinal motility: prenatal development and problems in infancy.

Deglutition, or swallowing, refers to the process of propulsion of a food bolus from the mouth into the stomach and involves the highly coordinated interplay of swallowing and breathing. At 34 weeks gestational age most neonates are capable of successful oral feeding if born at this time; however, the maturation of respiration is still in progress at this stage. Infants can experience congenital and developmental pharyngeal and/or gastrointestinal motility disorders, which might manifest clinically as gastro-oesophageal reflux (GER) symptoms, feeding difficulties and/or refusal, choking episodes and airway changes secondary to micro or overt aspiration. These problems might lead to impaired nutritional intake and failure to thrive. These gastrointestinal motility disorders are mostly classified according to the phase of swallowing in which they occur, that is, the oral preparatory, oral, pharyngeal and oesophageal phases. GER is a common phenomenon in infancy and is referred to as GERD when it causes troublesome complications. GER is predominantly caused by transient relaxation of the lower oesophageal sphincter. In oesophageal atresia, oesophageal motility disorders develop in almost all patients after surgery; however, a congenital origin of disordered motility has also been proposed. This Review highlights the prenatal development of upper gastrointestinal motility and describes the most common motility disorders that occur in early infancy.

Low rates of adherence for tumor necrosis factor-α inhibitors in Crohn's disease and rheumatoid arthritis: results of a systematic review.

AIM: To investigate adherence rates in tumor necrosis factor-α (TNF-α)-inhibitors in Crohn's disease (CD) and rheumatoid arthritis (RA) by systematic review of medical literature. METHODS: A structured search of PubMed between 2001 and 2011 was conducted to identify publications that assessed treatment with TNF-α inhibitors providing data about adherence in CD and RA. Therapeutic agents of interest where adalimumab, infliximab and etanercept, since these are most commonly used for both diseases. Studies assessing only drug survival or continuation rates were excluded. Data describing adherence with TNF-α inhibitors were extracted for each selected study. Given the large variation between definitions of measurement of adherence, the definitions as used by the authors where used in our calculations. Data were tabulated and also presented descriptively. Sample size-weighted pooled proportions of patients adherent to therapy and their 95%CI were calculated. To compare adherence between infliximab, adalimumab and etanercept, the adherence rates where graphed alongside two axes. Possible determinants of adherence were extracted from the selected studies and tabulated using the presented OR. RESULTS: Three studies on CD and three on RA were identified, involving a total of 8147 patients (953 CD and 7194 RA). We identified considerable variation in the definitions and methodologies of measuring adherence between studies. The calculated overall sample size-weighted pooled proportion for adherence to TNF-α inhibitors in CD was 70% (95%CI: 67%-73%) and 59% in RA (95%CI: 58%-60%). In CD the adherence rate for infliximab (72%) was highercompared to adalimumab (55%), with a relative risk of 1.61 (95%CI: 1.27-2.03), whereas in RA adherence for adalimumab (67%) was higher compared to both infliximab (48%) and etanercept (59%), with a relative risk of 1.41 (95%CI: 1.3-1.52) and 1.13 (95%CI: 1.10-1.18) respectively. In comparative studies in RA adherence to infliximab was better than etanercept and etanercept did better than adalimumab. In three studies, the most consistent factor associated with lower adherence was female gender. Results for age, immunomodulator use and prior TNF-α inhibitors use were conflicting. CONCLUSION: One-third of both CD and RA patients treated with TNF-α inhibitors are non-adherent. Female gender was consistently identified as a negative determinant of adherence.