Comparison of weekly gluten immunogenic peptide measurement and conventional tools to assess adherence to the gluten-free diet in celiac disease: An observational prospective study

BACKGROUND

Adherence to the gluten-free diet (GFD) is critical to achieving symptom control and mucosal healing in celiac disease (CeD), but its assessment is difficult.

OBJECTIVES

We sought to compare stool gluten immunogenic peptides (GIPs) measurements over a 4-wk period with conventional tools commonly used to monitor compliance with a GFD.

METHODS

Consecutive adult patients with CeD attending the Small Bowel Section of the Buenos Aires Gastroenterology Hospital were invited to this observational study and were instructed to collect stool samples on Fridays for 4 consecutive weeks. Weekly mean stool GIP concentration was measured was estimated. GIP results were compared with a self-assessment scale of adherence, specific CeD serology, the celiac symptom index, and the assessment by an expert dietitian.

RESULTS

Fifty-three CeD patients were enrolled and those with stool GIP ≥0.65 μg/g/wk (n = 13; 24.5%) had higher serum concentrations of IgA deamidated gliadin peptides (DGPs) antibodies [69 (29-109) compared with 14 (13-29); P = 0.0005] and IgA tissue transglutaminase [42 (14-200) compared with 10 (7-16); P = 0.02], higher proportion of cases with IgA DGP antibodies >20 AU/mL (84.6% compared with 33.3%; P = 0.002), and a higher self-estimated adherence score [5 (4-9) compared with 9 (7-10); P = 0.003]. GIP did not correlate with celiac symptom index scores (55.6% compared with 30.8%; P = 0.9). Expert dietitian assessment identified 69% [odds ratio (OR): 5.25; 95% CI: 1.1-27.2; P = 0.01] of nonadherent cases when high stool GIP. Logistic regression analysis determined that IgA DGP (adjusted OR: 1.1; 95% CI: 1.01-1.11; P = 0.02) and males (adjusted OR: 28.3; 95% CI: 1.1-722.6; P = 0.04) were independently associated with excessive gluten exposure.

CONCLUSIONS

Weekly stool GIP identifies gluten exposure that is not always detected by commonly used GFD adherence assessment methods. The higher the concentration of stool GIP, the better the predictive value of serology and dietitian interviews. Stool GIP is a useful and practical test for GFD monitoring, particularly for risky gluten exposure in real-life scenarios.

Risk perception and knowledge of COVID-19 in patients with celiac disease

BACKGROUND

We recently demonstrated that the odds of contracting coronavirus disease 2019 (COVID-19) in patients with celiac disease (CeD) is similar to that of the general population. However, how patients with CeD perceive their COVID-19 risk may differ from their actual risk.

AIM

To investigate risk perceptions of contracting COVID-19 in patients with CeD and determine the factors that may influence their perception.

METHODS

We distributed a survey throughout 10 countries between March and June 2020 and collected data on demographics, diet, COVID-19 testing, and risk perceptions of COVID-19 in patients with CeD. Participants were recruited through various celiac associations, clinic visits, and social media. Risk perception was assessed by asking individuals whether they believe patients with CeD are at an increased risk of contracting COVID-19 when compared to the general population. Logistic regression was used to determine the influencing factors associated with COVID-19 risk perception, such as age, sex, adherence to a gluten-free diet (GFD), and comorbidities such as cardiac conditions, respiratory conditions, and diabetes. Data was presented as adjusted odds ratios (aORs)

RESULTS

A total of 10737 participants with CeD completed the survey. From them, 6019 (56.1%) patients with CeD perceived they were at a higher risk or were unsure if they were at a higher risk of contracting COVID-19 compared to the non-CeD population. A greater proportion of patients with CeD perceived an increased risk of contracting COVID-19 when compared to infections in general due to their CeD (56.1% vs 26.7%, P < 0.0001). Consequently, 34.8% reported taking extra COVID-19 precautions as a result of their CeD. Members of celiac associations were less likely to perceive an increased risk of COVID-19 when compared to non-members (49.5% vs 57.4%, P < 0.0001). Older age (aOR: 0.99; 95%CI: 0.99 to 0.99, P < 0.001), male sex (aOR: 0.84; 95%CI: 0.76 to 0.93, P = 0.001), and strict adherence to a GFD (aOR: 0.89; 95%CI: 0.82 to 0.96, P = 0.007) were associated with a lower perception of COVID-19 risk and the presence of comorbidities was associated with a higher perception of COVID-19 risk (aOR: 1.38; 95%CI: 1.22 to 1.54, P < 0.001).

CONCLUSION

Overall, high levels of risk perceptions, such as those found in patients with CeD, may increase an individual’s pandemic-related stress and contribute to negative mental health consequences. Therefore, it is encouraged that public health officials maintain consistent communication with the public and healthcare providers with the celiac community. Future studies specifically evaluating mental health in CeD could help determine the consequences of increased risk perceptions in this population.

Real-World Gluten Exposure in Patients With Celiac Disease on Gluten-Free Diets, Determined From Gliadin Immunogenic Peptides in Urine and Fecal Samples

BACKGROUND & AIMS

It is not clear how often patients who are on gluten-free diets (GFDs) for treatment of celiac disease still are exposed to gluten. We studied levels of gluten immunogenic peptides (GIP) in fecal and urine samples, collected over 4 weeks, from patients with celiac disease on a long-term GFD.

METHODS

We performed a prospective study of 53 adults with celiac disease who had been on a GFD for more than 2 years (median duration, 8 y; interquartile range, 5-12 y) in Argentina. At baseline, symptoms were assessed by the celiac symptom index questionnaire. Patients collected stool each Friday and Saturday and urine samples each Sunday for 4 weeks. We used a commercial enzyme-linked immunosorbent assay to measure GIP in stool and point-of-care tests to measure GIP in urine samples.

RESULTS

Overall, 159 of 420 stool and urine samples (37.9%) were positive for GIP; 88.7% of patients had at least 1 fecal or urine sample that was positive for GIP (median, 3 excretions). On weekends (urine samples), 69.8% of patients excreted GIP at least once, compared with 62.3% during weekdays (stool). The number of patients with a sample that was positive for GIP increased over the 4-week study period (urine samples in week 1 vs week 4: P < .05). Patients with symptoms had more weeks in which GIP was detected in stool than patients without symptoms (P < .05). The number of samples that were positive for GIP correlated with titers of deamidated gliadin peptide IgA in patients' blood samples, but not with levels of tissue transglutaminase.

CONCLUSIONS

Patients with celiac disease on a long-term GFD still frequently are exposed to gluten. Assays to detect GIP in stool and urine might be used to assist dietitians in assessment of GFD compliance.

Gluten immunogenic peptide excretion detects dietary transgressions in treated celiac disease patients

BACKGROUND

Life-long removal of gluten from the diet is currently the only way to manage celiac disease (CeD). Until now, no objective test has proven useful to objectively detect ingested gluten in clinical practice. Recently, tests that determine consumption of gluten by assessing excretion of gluten immunogenic peptides (GIP) in stool and urine have been developed. Their utility, in comparison with conventional dietary and analytical follow-up strategies, has not been fully established.

AIM

To assess the performance of enzyme-linked immunosorbent assay (ELISA) and point-of-care tests (PoCTs) for GIP excretion in CeD patients on gluten-free diet (GFD).

METHODS

We conducted an observational, prospective, cross-sectional study in patients following a GFD for at least two years. Using the Gastrointestinal Symptom Rating Scale questionnaire, patients were classified at enrollment as asymptomatic or symptomatic. Gluten consumption was assessed twice by 3-d dietary recall and GIP excretion (by ELISA in stool and PoCTs (commercial kits for stool and urine) in two consecutive samples. These samples and dietary reports were obtained 10 day apart one from the other. Patients were encouraged to follow their usual GFD during the study period.

RESULTS

Forty-four patients were enrolled, of which 19 (43.2%) were symptomatic despite being on a GFD. Overall, 83 sets of stool and/or urine samples were collected. Eleven out of 44 patients (25.0%) had at least one positive GIP test. The occurrence of at least one positive test was 32% in asymptomatic patients compared with 15.8% in symptomatic patients. GIP was concordant with dietary reports in 65.9% of cases (Cohen´s kappa: 0.317). PoCT detected dietary indiscretions. Both ELISA and PoCT in stool were concordant (concomitantly positive or negative) in 67 out of 74 (90.5%) samples. Excretion of GIP was detected in 7 (8.4%) stool and/or urine samples from patients considered to be strictly compliant with the GFD by dietary reports.

CONCLUSION

GIP detects dietary transgressions in patients on long-term GFD, irrespective of the presence of symptoms. PoCT for GIP detection constitutes a simple home-based method for self-assessment of dietary indiscretions.

Impaired Bone Microarchitecture Improves After One Year On Gluten-Free Diet: A Prospective Longitudinal HRpQCT Study in Women With Celiac Disease

We have recently identified a significant deterioration of bone microarchitecture in premenopausal women with newly diagnosed celiac disease (CD) using high-resolution peripheral quantitative computed tomography (HRpQCT). The aim of this work was to assess changes in bone microarchitecture after 1 year on a gluten-free diet (GFD) in a cohort of premenopausal women. We prospectively enrolled 31 consecutive females at diagnosis of CD; 26 of them were reassessed 1 year after GFD. They all underwent HRpQCT scans of distal radius and tibia, areal BMD by DXA, and biochemical tests (bone-specific parameters and CD serology) at both time points. Secondary, we compared 1-year results with those of a control group of healthy premenopausal women of similar age and BMI in order to assess whether the microarchitectural parameters of treated CD patients had reached the values expected for their age. Compared with baseline, the trabecular compartment in the distal radius and tibia improved significantly (trabecular density, trabecular/bone volume fraction [BV/TV] [p < 0.0001], and trabecular thickness [p = 0.0004]). Trabecular number remained stable in both regions. Cortical density increased only in the tibia (p = 0.0004). Cortical thickness decreased significantly in both sites (radius: p = 0.03; tibia: p = 0.05). DXA increased in all regions (lumbar spine [LS], p = 0.01; femoral neck [FN], p = 0.009; ultradistal [UD] radius, p = 0.001). Most parameters continued to be significantly lower than those of healthy controls. This prospective HRpQCT study showed that most trabecular parameters altered at CD diagnosis improved significantly by specific treatment (GFD) and calcium and vitamin D supplementation. However, there were still significant differences with a control group of women of similar age and BMI. In the prospective follow-up of this group of patients we expect to be able to assess whether bone microarchitecture attains levels expected for their age. © 2016 American Society for Bone and Mineral Research.

Significant bone microarchitecture impairment in premenopausal women with active celiac disease

Patients with active celiac disease (CD) are more likely to have osteoporosis and increased risk of fractures. High-resolution peripheral quantitative computed tomography (HR-pQCT) permits three-dimensional exploration of bone microarchitectural characteristics measuring separately cortical and trabecular compartments, and giving a more profound insight into bone disease pathophysiology and fracture. We aimed to determine the volumetric and microarchitectural characteristics of peripheral bones-distal radius and tibia-in an adult premenopausal cohort with active CD assessed at diagnosis. We prospectively enrolled 31 consecutive premenopausal women with newly diagnosed CD (median age 29 years, range: 18-49) and 22 healthy women of similar age (median age 30 years, range 21-41) and body mass index. Compared with controls, peripheral bones of CD patients were significantly lower in terms of total volumetric density mg/cm(3) (mean ± SD: 274.7 ± 51.7 vs. 324.7 ± 45.8, p 0.0006 at the radius; 264.4 ± 48.7 vs. 307 ± 40.7, p 0.002 at the tibia), trabecular density mg/cm(3) (118.6 ± 31.5 vs. 161.9 ± 33.6, p<0.0001 at the radius; 127.9 ± 28.7 vs. 157.6 ± 15.6, p < 0.0001 at the tibia); bone volume/trabecular volume ratio % (9.9 ± 2.6 vs. 13.5 ± 2.8, p<0.0001 at the radius; 10.6 ± 2.4 vs. 13.1 ± 1.3, p < 0.0001 at the tibia); number of trabeculae 1/mm (1.69 ± 0.27 vs. 1.89 ± 0.26, p 0.009 at the radius; 1.53 ± 0.32 vs. 1.80 ± 0.26, p 0.002 at the tibia); and trabecular thickness mm (0.058 ± 0.010 vs. 0.071 ± 0.008, p < 0.0001 at the radius with no significant difference at the tibia). Cortical density was significantly lower in both regions (D comp mg/cm(3) 860 ± 57.2 vs. 893.9 ± 43, p 0.02; 902.7 ± 48.7 vs. 932.6 ± 32.6, p 0.01 in radius and tibia respectively). Although cortical thickness was lower in CD patients, it failed to show any significant inter-group difference (a-8% decay with p 0.11 in both bones). Patients with symptomatic CD (n = 22) had a greater bone microarchitectural deficit than those with subclinical CD. HR-pQCT was used to successfully identify significant deterioration in the microarchitecture of trabecular and cortical compartments of peripheral bones. Impairment was characterized by lower trabecular number and thickness-which increased trabecular network heterogeneity-and lower cortical density and thickness. In the prospective follow-up of this group of patients we expect to be able to assess whether bone microarchitecture recovers and to what extend after gluten-free diet.