Less, but not gone-gluten-free diet effects on fatigue in celiac disease: a prospective controlled study.

Introduction: Fatigue is a frequent complaint in patients with celiac disease. A gluten-free diet is the only established treatment for celiac disease, but how this diet influences fatigue is uncertain. We aimed to investigate fatigue prevalence, severity, and associated factors in patients with celiac disease, at diagnosis and at 1 year after commencing a gluten-free diet. Methods: 78 patients with serologically and histologically verified celiac disease, 78 age- and sex-matched healthy subjects. Primary endpoints were Fatigue Visual Analog Scale (fVAS), Fatigue Severity Scale (FSS), and inverted Vitality subscale of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36vs). Clinically relevant fatigue was defined as: FSS score ≥ 4, fVAS score ≥ 50 mm, or inverted SF-36vs score ≥ 65. Higher scores represented more fatigue. Results: Fatigue was reduced after a 12-month gluten-free diet. Median scores changed from 3.8 (interquartile range [IQR]: 2.2 to 4.8) to 1.9 (IQR: 1.4 to 3.5) for FSS, from 44.5 (IQR: 18.8 to 66.0) to 15.5 (IQR: 7.8 to 43.3) for fVAS, and from 65 (IQR: 40 to 75) to 35 (IQR: 25 to 55) for inverted SF-36vs (p < 0.001 for all). Fatigue prevalence also declined after treatment. However, scores were significantly higher in patients compared to control subjects. Higher fatigue scores were associated with depression and pain, but not with signs of disease activity or nutritional deficiency. Conclusion: At diagnosis, patients with celiac disease frequently had severe fatigue. Fatigue declined after a gluten-free diet, but it remained higher than that observed in healthy subjects. Clinical trial registration: ClinicalTrials.gov, Identifier NCT01551563.

High mobility group box 1 and a network of other biomolecules influence fatigue in patients with Crohn's disease.

BACKGROUND: Fatigue is common in patients with chronic inflammatory and autoimmune diseases, often with a severe impact on the patient's daily life. From a biological point of view, fatigue can be regarded as an element of the sickness behavior response, a coordinated set of responses induced by pathogens to enhance survival during an infection and immunological danger. The mechanisms are not fully understood but involve activation of the innate immune system, with pro-inflammatory cytokines, in particular interleukin (IL)-1ß, acting on cerebral neurons. These mechanisms are also active during chronic inflammatory conditions. High mobility group box 1 (HMGB1) protein has interleukin-1 like properties and is a strong inducer of innate immune responses. Its role in generation of fatigue is not clarified. Emerging evidence indicates that also other biomolecules may influence sickness behavior. We aimed to elucidate how HMGB1 influences fatigue in patients with Crohn's disease, and how the protein interacts with other candidate biomarkers of fatigue. METHODS: In 56 patients with newly diagnosed Crohn's disease, fatigue was evaluated using three different fatigue instruments: the fatigue visual analog scale (fVAS), Fatigue Severity Scale (FSS), and the vitality subscale of Medical Outcomes Study Short-Form Health Survey (SF-36vs). The biochemical markers IL-1 receptor antagonist (RA), soluble IL-1 receptor type 2 (sIL-RII), heat shock protein 90 alpha (HSP90α), HMGB1, anti-fully reduced (fr)HMGB1 antibodies (abs), hemopexin (HPX), and pigment epithelium-derived factor (PEDF) were measured in plasma. Multivariable regression and principal component analyses (PCA) were applied. RESULTS: Multivariable regression analyses revealed significant contributions to fatigue severity for HMGB1 in the FSS model, HSP90α in the fVAS model and IL-1RA in the SF-36vs model. Depression and pain scores contributed to all three models. In PCA, two components described 53.3% of the variation. The "inflammation and cellular stress dimension" was dominated by IL-1RA, sIL-1RII, HSP90α, HPX, and PEDF scores, where the "HMGB1 dimension" was dominated by HMGB1, anti-frHMGB1 abs, and fVAS scores. CONCLUSION: This study supports the hypothesis that HMGB1 and a network of other biomolecules influence fatigue severity in chronic inflammatory conditions. The well-known association with depression and pain is also acknowledged.

The Effect of Biological Treatment on Fatigue in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis.

BACKGROUND: Fatigue is a frequent complaint in patients with inflammatory bowel disease. Biological drugs have demonstrated beneficial effects on some extraintestinal manifestations, but the effect on fatigue is not clear. OBJECTIVE: This study investigated the effects of biological and small molecule drugs approved for inflammatory bowel disease on fatigue. METHODS: We performed a systematic review and meta-analysis of randomized, placebo-controlled trials reporting Federal Drug Agency (FDA)-approved biological and small molecule drugs for use in ulcerative colitis and Crohn's disease in which measures of fatigue were recorded before and after treatment. Only induction studies were included. Maintenance studies were excluded. We searched Embase (Ovid), Medline (Ovid), PsycINFO (Ovid), Cinahl (EBSCOhost), Web of Science Core Collection, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov in May 2022. Risk of bias was analyzed using the Cochrane risk-of-bias tool. Standardized mean difference was used to measure the treatment effect. RESULTS: A total of seven randomized controlled trials composed of 3835 patients were included in the meta-analysis. All of the studies included patients with moderately to severely active ulcerative colitis or Crohn's disease. The studies used three different generic fatigue instruments: the Functional Assessment of Chronic Illness Therapy-Fatigue and the Short Form 36 Health Survey Vitality Subscale versions 1 and 2. Overall treatment with biological or small molecule agents showed a beneficial effect compared with placebo, with a standardized mean difference of 0.25 (95% confidence interval 0.15-0.34, p < 0.001). The effect was independent of type of drug or subtype of inflammatory bowel disease. DISCUSSION: The risk of bias was considered to be low for all domains except for missing outcome data. Even though the included studies were of high methodological quality, the review is limited by the small number of studies included and that the available studies were not designed to evaluate fatigue specifically. CONCLUSION: Biological and small molecule drugs used in inflammatory bowel disease have a consistent, though small, beneficial effect on fatigue.

"Out of the box" new therapeutic strategies for Crohn´s disease: moving beyond biologics.

New treatment options beyond immunosuppression have emerged in recent years for patients with Crohn´s disease (CD), a chronic systemic condition affecting primarily the gut with great impact in the quality of life. The cause of CD is largely unknown, and a curative treatment is not yet available. In addition, despite the growing therapeutic armamentarium in recent years almost half of the patients don´t achieve a sustained response over time. Thus, new therapeutic strategies are urgently needed. In this review, we discuss the current state of promising new "out of the box" possibilities to control chronic inflammation beyond current pharmacological treatments, including: exclusive enteral nutrition, specific diets, cell therapies using T regs, hyperbaric oxygen, fecal microbiota transplantation, phage therapy, helminths, cannabis and vagal nerve stimulation. The exploration of original and novel therapeutic modalities is key to address their potential as main or complementary treatments in selected CD populations in order to increase efficacy, minimize side effects and improve quality of life of patients.

“Out of the box” new therapeutic strategies for Crohn´s disease: moving beyond biologics

New treatment options beyond immunosuppression have emerged in recent years for patients with Crohn´s disease (CD), a chronic systemic condition affecting primarily the gut with great impact in the quality of life. The cause of CD is largely unknown, and a curative treatment is not yet available. In addition, despite the growing therapeutic armamentarium in recent years almost half of the patients don´t achieve a sustained response over time. Thus, new therapeutic strategies are urgently needed. In this review, we discuss the current state of promising new “out of the box” possibilities to control chronic inflammation beyond current pharmacological treatments, including: exclusive enteral nutrition, specific diets, cell therapies using T regs, hyperbaric oxygen, fecal microbiota transplantation, phage therapy, helminths, cannabis and vagal nerve stimulation. The exploration of original and novel therapeutic modalities is key to address their potential as main or complementary treatments in selected CD populations in order to increase efficacy, minimize side effects and improve quality of life of patients (AU)

Histologic healing and factors associated with complete remission following conventional treatment in ulcerative colitis.

Background: Endoscopic and histological activity scores in ulcerative colitis (UC) are associated with clinical outcomes and have become important targets of clinical trials. However, these endpoints have been scarcely investigated in patients receiving only conventional treatment. Objective: We aimed to assess the deep and complete remission rates after 3 months of conventional treatment in patients with newly diagnosed UC with moderate to severe endoscopic activity. We also aimed to investigate whether selected clinical and biochemical variables at baseline were associated with complete remission status after 3 months. Design: This was a prospective cohort study. Methods: Newly diagnosed patients with active UC commencing 5-aminosalicylate, corticosteroid, and/or azathioprine treatment were consecutively included. Clinical, biochemical, endoscopic, and histological data were collected at baseline and after 3 months. Rates of clinical remission (Partial Mayo Score ⩽ 2), mucosal healing (Mayo Endoscopic Score ⩽ 1), and histologic healing (Nancy Index ⩽ 1) were determined. Deep remission was assessed as clinical remission plus mucosal healing and complete remission as deep remission plus histologic healing. Predictors of complete remission were identified by logistic regression. Results: A total of 180 patients were included in the study. Deep remission and complete remission occurred in 62.8% and 42.2% of patients, respectively. Thus, of patients in deep remission one-third had persistent histologic activity. Histologic activity in mucosally healed patients was associated with higher symptom scores and faecal calprotectin levels. Of baseline variables, less endoscopic distribution and disease activity showed strongest association with achieving complete remission, and limited distribution in combination with moderate activity gave highest odds for complete remission (odds ratio: 4.1, 95% confidence interval: 7.69-2.18). Conclusion: In patients with mucosal healing, persistent histologic activity was a common finding and was associated with increased disease activity. Pancolitis and severe inflammatory activity at baseline were associated with lower complete remission rates.

Fatigue: a frequent and biologically based phenomenon in newly diagnosed celiac disease.

Fatigue is increasingly recognized as a major complaint in patients with chronic inflammatory and autoimmune diseases. Although fatigue is assumed to represent a significant problem in celiac disease, existing knowledge is scarce, and opinions are conflicting. This study aimed to investigate the prevalence and severity of fatigue in patients with newly diagnosed celiac disease and compare it with healthy control subjects. Ninety patients with newly diagnosed celiac disease were compared with 90 age- and sex-matched healthy subjects. The primary endpoints were fatigue severity as measured by: the fatigue Visual Analog Scale (fVAS), the Fatigue Severity Scale (FSS), and the inverted Vitality subscale of the MOS36 (SF-36vs). Higher scores indicate more severe fatigue. Clinically relevant fatigue was determined using predefined cut-off values. Secondary endpoints were the associations between fatigue, and sex, age, depression, pain, and selected biochemical variables. The median (IQR) fVAS-scores were 43.0 (18.0-64.5) in patients, and 9.0 (2.0-16.0) in the control group (p < 0.001); and the FSS scores 3.8 (2.0-4.8) in patients, and 1.4 (1.0-1.9) in control subjects (p < 0.001). Inverted SF-36vs scores had a mean (SD) value of 58.8 (23.6) in patients, and 29.7 (14.3) in healthy subjects (p < 0.001). The presence of clinically relevant fatigue ranged from 41 to 50% in patients. Increased fatigue severity was associated with female sex, younger age, and elevated pain and depression scores, but not with levels of selected biochemical variables, including hemoglobin. Fatigue is a severe and frequent phenomenon in patients with untreated celiac disease.

The multidimensional fatigue inventory (MFI-20): psychometrical testing in a Norwegian sample of inflammatory bowel disease (IBD) patients.

OBJECTIVES: To evaluate the psychometric properties of the Norwegian version of the multidimensional fatigue inventory (MFI-20) in patients with inflammatory bowel disease. METHODS: Participants were recruited from nine hospitals in the southeastern and western parts of Norway. Clinical and sociodemographic data were collected, and participants completed the MFI-20, as well as the Fatigue Questionnaire (FQ). In addition to a confirmatory factor analysis, validity, reliability, test-retest and responsiveness were evaluated. RESULTS: In total, 410 patients were included. The Norwegian MFI-20 had an acceptable model fit when compared to the original five-dimensional structure. A positive correlation was observed between the dimensions of MFI-20 and the FQ. MFI-20 scores increased according to subjective disease activity, but no differences were observed when using a calprotectin cut-off < or > =250 µg/g mg/kg. All MFI-20 dimensions except 'reduced motivation' in both ulcerative colitis (UC) and Crohn's disease (CD) patients had alpha Cronbach alpha values ≥70, and test-retest reliability revealed good to excellent values. Merely one dimension (Reduced activity) in UC patients reporting improvement did not reach the threshold for acceptable responsiveness according to Guyatt statistics. CONCLUSIONS: The Norwegian version of MFI-20 is valid, reliable and responsive. The instrument can safely be used in studies using fatigue as an endpoint.

The influence of disease activity on fatigue in patients with ulcerative colitis - a longitudinal study.

OBJECTIVE: The relationship between the disease activity of ulcerative colitis and fatigue is unclear. We investigated how reaching deep remission versus remaining in active disease influenced the severity of fatigue. MATERIALS AND METHODS: We included 149 consecutive patients in a longitudinal study. Patients were re-examined after 3 months of conventional treatment and dichotomized into A: Active disease or B: Deep remission. The Partial Mayo Score (PMS) was recorded in all patients. Fatigue was rated using the fatigue visual analog scale (fVAS), Fatigue Severity Scale (FSS), and Short Form-36 Vitality Subscale (SF-36vs). A control group of 22 age and sex-matched healthy subjects were included as controls for patients reaching deep remission. RESULTS: After 3 months there were no significant differences in fVAS, FSS and SF-36vs scores in patients with active disease compared to patients reaching deep remission, when adjusting for baseline fatigue scores. Patients in remission based on MES-UC scores had no significant reduction in fatigue scores, whereas patients in remission based on PMS had all three fatigue scores reduced. However, patients reaching deep remission still had higher fVAS and lower SF-36vs scores compared to healthy control subjects. CONCLUSIONS: After 3 months of conventional treatment there were no differences in fatigue severity in patients reaching deep remission compared with patients still having active disease. Fatigue was more pronounced in patients in deep remission than in healthy subjects, and was associated with subjective and not objective measures of disease activity. This indicates that other potent factors than inflammation influence fatigue in UC.

Fatigue and expression of heat-shock protein genes in plaque psoriasis.

BACKGROUND: Chronic fatigue is common in patients with psoriasis, and heat-shock proteins (HSPs) have been suggested to influence fatigue. AIM: To evaluate gene expression patterns of selected HSPs in patients with psoriasis with high vs. low fatigue. METHODS: Fatigue was assessed using the fatigue Visual Analogue Scale, and disease activity by the Psoriasis Area and Severity Index. Peripheral blood transcriptional profiling was performed using RNA sequencing (RNA-seq) of HSP genes from 10 patients with high fatigue, and compared with 10 patients with low fatigue. HSPB11, HSPBAP1, HSPA14, HSPA9P1, HSP90B1 and HSP90AB1 contributed most to separation of the two groups in a principal components analysis. Four of these genes (HSPB11, HSPA14, HSP90B1 and HSP90AB1) were further investigated by real-time reverse transcription quantitative PCR (RT-qPCR) in 20 patients with high- and 20 patients with low-fatigue scores. RESULTS: Both RNA-seq and RT-qPCR analyses revealed a tendency to higher expression levels of HSPB11 and lower expression of HSP90B1 in the high- vs. the low-fatigue group. Psoriasis disease activity had no influence on the expression levels of the studied HSP genes. CONCLUSION: Overall, the results suggest that some HSPs are involved in generation of fatigue in psoriasis, supporting the hypothesis that downregulatory innate immune responses influence fatigue.

Anti-HMGB1 auto-Abs influence fatigue in patients with Crohn's disease.

Fatigue is common in all chronic inflammatory and autoimmune diseases. A conceptual model for understanding the biological basis of fatigue describes it as being a part of the sickness behaviour response generated by pro-inflammatory cytokines and other mediators. We hypothesised that the pro-inflammatory high mobility group box 1 (HMGB1) protein is a fatigue-inducing molecule and that auto-Abs against HMGB1 reduce fatigue. We measured Abs against disulphide (ds) HMGB1 and fully reduced (fr) HMGB1 in plasma from 57 patients with Crohn's disease. Fatigue was rated using the fatigue visual analogue scale (fVAS) and disease activity with faecal calprotectin, C-reactive protein and the Simple Endoscopic Score for Crohn's disease. Multivariable regression models identified anti-dsHMGB1 and anti-frHMGB1 Abs as the strongest contributing factors for fVAS scores (B = -29.10 (P = 0.01), R2 = 0.17, and B = -17.77 (P = 0.01), R2 = 0.17, respectively). Results indicate that anti-HMGB1 auto-Abs alleviate fatigue possibly by down-regulating HMGB1-induced sickness behaviour.

Determination of lower cut-off levels of adalimumab associated with biochemical remission in Crohn's disease.

BACKGROUND AND AIM: Adalimumab is administered and dosed using a standardized treatment regimen. Although therapeutic drug monitoring (TDM) may help optimize treatment efficacy, the lower cut-off concentration of adalimumab needed to retain disease remission has not been established. This cross-sectional study of patients with Crohn's disease on stable medication aimed to determine a lower therapeutic drug concentration threshold of adalimumab associated with biochemical disease remission. METHODS: C-reactive protein (CRP) and fecal calprotectin were used as established markers and albumin as an explorative marker of disease activity. Time since introduction, treatment interval, drug dosage, serum drug concentration and antidrug antibodies, disease duration, age, and sex were recorded. RESULTS: The study included 101 patients who were divided into "active disease" and "remission" groups for inflammatory markers based on cut-off levels of 5 mg/L for CRP and 50 mg/kg for fecal calprotectin. Cut-off levels for albumin of 36.5 and 41.5 g/L were also added as further indicatives of remission. Receiver operating characteristic analysis found optimal thresholds for adalimumab associated with remission at 6.8-7.0 mg/L for the combination of CRP and fecal calprotectin and when combining CRP, fecal calprotectin, and albumin. CONCLUSIONS: In patients with Crohn's disease, serum adalimumab of at least 6.8 mg/L was associated with biochemical disease remission based on CRP and fecal calprotectin, supporting the use of TDM to ensure disease control. Albumin should be further tested in this setting.

Pain Severity and Vitamin D Deficiency in IBD Patients.

Background: Pain and vitamin D deficiency are common in inflammatory bowel disease (IBD). Disease activity, fatigue, frequent relapses, prior surgery and psychological factors all seem to influence the experience of pain in IBD. Vitamin D deficiency has been associated with muscle and skeletal pain. This study aimed to determine whether there is an association between vitamin D deficiency and severity of pain in patients with IBD, and to investigate the influence of other socio-demographic and psychological variables on the experience of pain. Methods: Patients with IBD were recruited from nine hospitals in Norway in a multicenter cross-sectional study. The Brief Pain Inventory (BPI) questionnaire was used to measure pain. Disease activity was assessed using clinical disease activity indices, C-reactive protein (CRP) and fecal calprotectin. Regression models were fitted to explore a possible association between 25-hydroxyvitamin D and pain severity. Results: Of 407 patients included in the analyses, 229 (56%) had Crohn's disease (CD) and 178 (44%) had ulcerative colitis (UC). Vitamin D deficiency was present in half (203/407) of patients. Presence of pain was reported by 76% (309/407). More severe pain was associated with female gender and increased disease activity scores, but not with increased CRP or fecal calprotectin. In CD, patients without prior intra-abdominal surgery reported more severe pain. In multivariate analyses, there was no association between 25-hydroxyvitamin D and pain severity. Conclusions: In this study, no significant association between pain severity and vitamin D deficiency was revealed in patients with IBD.

Fatigue in celiac disease: A review of the literature.

Fatigue is increasingly recognized as a significant problem in patients with chronic inflammatory and autoimmune diseases. In celiac disease, a chronic immune-mediated disease triggered by dietary gluten, conflicting opinions exist regarding both the size of the problem and the effect of a gluten-free diet (GFD) on fatigue. We reviewed the existing literature regarding fatigue in celiac disease. We conducted a systematic search in the Embase, Ovid Medline, and Cochrane databases using subject terms from controlled vocabularies. Articles were reviewed based on language, type of article, title, and abstract or full text. Eighteen articles were finally selected for review. Fatigue was significantly greater in patients with celiac disease compared to healthy control subjects. Fatigue prevalence ranged from 8 to 100%. Fatigue severity was assessed in six studies. The fatigue visual analogue scale was the most frequently used fatigue instrument with scores from 57 to 79 prior to starting a GFD and from 39 to 59 in patients on a GFD. Seven studies investigated the effect of a GFD on fatigue, including five studies that reported less fatigue while on the diet and two studies that showed no significant difference. This review concludes that fatigue is a substantial complaint in patients with celiac disease. A GFD seems to reduce fatigue, but existing data are limited.

A case of Ménétriere´s disease treated with the monoclonal antibody cetuximab.

Ménétriere´s disease is a rare disorder of the body and fundus of the stomach, characterized by a massive proliferation of the foveolar cells and subsequent excess mucous secretion. This results in hypoproteinemia due to loss of serum proteins across the gastric mucosa. The cause of Ménétriere´s disease is unknown, and due to the irreversible and premalignant character of the disorder, the patients affected have been subdued to gastrectomy as the only curable treatment. Epidermial growth factor (EGF) has been implicated in the pathogenesis, a finding that makes the disorder receptive to monoclonal antibody treatment against the EGF receptor. In this case report, we present a 41-year-old woman referred to our emergency department due to dizziness, nausea, and vomiting. A thorough medical investigation, combining clinical history, laboratory investigations, an upper endoscopy with full-thickness snare biopsies, and a CT scan confirmed Ménétriere´s disease, and she was successfully treated with the monoclonal antibody cetuximab.

Fatigue is common and severe in patients with mastocytosis.

Chronic fatigue is a common phenomenon in inflammatory and autoimmune conditions, in cancer, and in neurodegenerative diseases. Although pain and psychological factors influence fatigue, there is an increasing understanding that there is a genetic basis, and that activation of the innate immune system is an essential generator of fatigue. Mast cells are important actors in innate immunity and serve specialized defense responses against parasites and other pathogens. They are also major effector cells in allergic reactions. Primary disorders causing constitutively hyperactivity of mast cells are called mastocytosis and are frequently due to a gain-of-function mutation of the KIT gene encoding the transmembrane tyrosine kinase receptor. It is a clinical experience that patients with mast cell disorders suffer from fatigue, but there is a lack of scientific literature on the phenomenon. We performed a controlled study of fatigue in mastocytosis patients and document a 54% prevalence of clinical significant fatigue.

Fatigue is not associated with vitamin D deficiency in inflammatory bowel disease patients.

AIM: To investigate if vitamin D deficiency is associated with fatigue in patients with inflammatory bowel disease (IBD). METHODS: IBD patients were recruited from nine hospitals in the southeastern and western regions of Norway to participate in a multicenter cross-sectional study lasting from March 2013 to April 2014. Data were collected by interviews, from medical records and laboratory tests. The Fatigue Questionnaire (FQ) was used to measure fatigue. Linear and logistic regression models were applied to explore the possible association between vitamin D deficiency and total fatigue scores and chronic fatigue, respectively. The analyses were adjusted for age, gender, disease activity, depressive symptoms and sleep disturbance. RESULTS: In total, 405 patients were included in the analyses, of which 227 (56%) had Crohn's disease (CD) and 178 (44%) had ulcerative colitis (UC). Vitamin D deficiency (< 50 nmol/L) was present in half (203/405) of the patients. Chronic fatigue was reported by 116 (29%) of all included patients with substantial fatigue reported by 194 (48%). Vitamin D levels were neither associated with total fatigue nor with chronic fatigue. Higher total fatigue scores and chronic fatigue were both associated with increased disease activity scores in patients with UC and CD, but not with increased CRP or fecal calprotectin. In UC patients, female gender was associated with fatigue in the univariate analysis, but no such difference was found when adjusted for elevated disease activity scores. Sleep disturbance and more depressive symptoms were associated with total fatigue scores in both UC and CD patients, but with chronic fatigue only in CD patients. CONCLUSION: In this study, no significant association between fatigue and vitamin D deficiency in IBD patients was revealed.

Subtherapeutic concentrations of infliximab and adalimumab are associated with increased disease activity in Crohn's disease.

BACKGROUND: Low anti-tumor necrosis factor α (TNFα) serum concentrations may result in lack of treatment response in patients with inflammatory bowel disease. We determined the anti-TNFα drug concentrations in patients with inflammatory bowel disease and investigated whether or not subtherapeutic drug concentrations were associated with increased levels of disease activity. METHODS: In a single-center cross-sectional study, we included patients with ulcerative colitis or Crohn's disease who were receiving infliximab or adalimumab maintenance therapy. Demographic data, disease activity symptom scores (Partial Mayo Score, Harvey Bradshaw Index), inflammatory markers [C-reactive protein (CRP), fecal calprotectin], antidrug antibodies and serum drug concentrations were recorded. Therapeutic drug concentrations were defined as 3-8 mg/liter for infliximab and 5-12 mg/liter for adalimumab. RESULTS: Of 210 patients included, 137 (65.2%) had Crohn's disease. In the adalimumab group, subtherapeutic drug concentrations were measured in 16.7% of patients with ulcerative colitis and in 27.7% of patients with Crohn's disease. In the infliximab group, subtherapeutic drug concentrations were found in 23% (ulcerative colitis) and 30.3% (Crohn's disease) of patients. In Crohn's disease, subtherapeutic adalimumab concentrations were associated with higher fecal calprotectin and CRP concentrations compared with therapeutic concentrations. Subtherapeutic infliximab concentrations in patients with Crohn's disease were also associated with higher CRP concentrations compared with therapeutic concentrations. CONCLUSIONS: The prevalence of subtherapeutic drug levels ranged from 17% to 30%. In patients with Crohn's disease, subtherapeutic serum drug concentrations were associated with significantly higher disease activity with both anti-TNFα agents. These findings were not observed in patients with ulcerative colitis. Clinicaltrials.gov identifier [NCT02134054].