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, a large pediatric cohort study in North America found.
Because tTG-IgA assay performance varied widely across labs, diagnostic confirmation by a specialist is essential before gluten-targeted dietary changes are made, according to Denis Chang, MD, MS, of the Division of Gastroenterology and Nutrition at Boston Children’s Hospital in Boston, and colleagues reported in Pediatrics.
“Currently, small intestinal biopsy is the gold standard for diagnosing pediatric celiac disease, but recent European diagnostic criteria allow a nonbiopsy pathway for serologic diagnosis,” Chang told GI & Heaptology News. The European guidelines allow this pathway when a very high tTG-IgA is confirmed by a positive endomysial IgA antibody (EMA) in a second blood sample.
Those guidelines have not been adopted on this continent, however, so Chang’s group assessed the positive predictive value (PPV) of the North American tTG-IgA assay to identify histologic findings of celiac disease.
Another issue is the absence of a universal standard threshold across labs for a high antibody value. “Common assays used in North America differ in performance, and there are not many large multicenter studies looking at this issue. Hopefully, a standard will be developed in the near future. Before this serologic pathway can enter into our guidelines, this question needs to be addressed.”
Study Details
The multicenter retrospective study by Dr. Chang’s team looked at patients younger than 18 years from three pediatric hospitals in Canada and nine in the US who had an elevated tTG-IgA within 6 months of an esophagogastroduodenoscopy from January 2016 to December 2021. Biopsy-confirmed celiac disease was determined by the presence of intraepithelial lymphocytosis and villous atrophy. The primary outcomes were the PPV of an elevated tTG-IgA and a tTG-IgA at least 10 times the upper limit of normal (10x ULN).
The study cohort included 4019 children (63.3% female, 9% with type 1 diabetes, and 2% with Down syndrome). Histologic findings were consistent with celiac disease for 3321 children, for a PPV of 82.6% (95% CI, 81.4%-83.8%).
Among the 1739 (43.2%) children with tTG-IgA of at least 10x ULN, 1651 had biopsy-confirmed celiac disease, for a PPV 10x ULN of 94.9% (95% CI, 93.8%-95.9%). About 5% (n = 88) of positive-testing children did not have histologic findings of celiac disease, including 2% (n = 41) with normal histology.
Diagnostic accuracy of tTG-IgA varied widely among the assays used in North America, with a PPV range of 71.5%-88.8% and a PPV 10x ULN range of 89.3%-97.3%. Assays did not perform as well in children with type 1 diabetes: PPV 10x ULN of 89% (95% CI, 83.5%-92.8%).
In other notable findings, the EMA blood test only marginally improved specificity, as 76% of children without celiac disease, but with a tTG-IgA of at least 10x ULN had a positive EMA in the same sample.
While the study lends credence to the notion that a highly positive tTG-IgA correlates with enteropathy in most children, the 1 in 20 with a tTG-IgA greater than 10x ULN who did not have histologic findings diagnostic of celiac disease cannot be ignored. “This included 2% who had normal small intestinal biopsies on a gluten-containing unrestricted diet, highlighting the limitations of making a celiac disease diagnosis based solely upon a single, highly positive tTG-IgA level,” Chang and colleagues wrote.
Does this mean that substantial numbers of children with suspected celiac disease are being unnecessarily placed on gluten-restricted diets to no avail? “That’s a good question, but our retrospective data do not provide an answer to that,” Chang said. And what causes elevated autoantibodies in children who are not diagnosed with celiac disease? “That is also a question that will require further research,” he said.
Commenting on the study but not involved in it, Supriya Nair, MD, a pediatric gastroenterologist at UTHealth Houston, called it “very interesting because it highlights for primary care physicians that we may need endoscopic evaluation more than we thought.” This is particularly true given the lack of standardized laboratory values noted in the study.
Nair said that some children with high seromarker levels but no discernible lesions may develop celiac disease later. “It may be that the markers are not yet causing inflammation in the bowel. These patients must be monitored to see if levels stay high or come down.”
In her practice, she has seen some children who have been put on gluten-free diets prematurely. “But it’s very important to get an accurate, official confirmation with endoscopy because of the ramifications of a celiac diagnosis,” she said. “This is a lifelong condition, and the diet is not easy to follow, especially in North America.” And for children, especially, there are restrictive social impacts and the constant need to be aware of what they’re eating and the danger of cross-contamination in foods, she said.
Chang hopes these data will be pivotal in helping medical societies develop new North American guidelines. In the meantime, pediatricians and primary doctors need to be aware that a high number on a tTG-IgA test does not always mean the presence of celiac disease, although it could be a harbinger of its future development. “Further confirmation by a specialist is essential.”
The study was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health. Chang and Nair reported having no competing interests. Several study authors reported receiving research support from and serving as consultants or members of data safety monitoring boards for pharmaceutical companies.
A version of this article appeared on Medscape.com.
, a large pediatric cohort study in North America found.
Because tTG-IgA assay performance varied widely across labs, diagnostic confirmation by a specialist is essential before gluten-targeted dietary changes are made, according to Denis Chang, MD, MS, of the Division of Gastroenterology and Nutrition at Boston Children’s Hospital in Boston, and colleagues reported in Pediatrics.
“Currently, small intestinal biopsy is the gold standard for diagnosing pediatric celiac disease, but recent European diagnostic criteria allow a nonbiopsy pathway for serologic diagnosis,” Chang told GI & Heaptology News. The European guidelines allow this pathway when a very high tTG-IgA is confirmed by a positive endomysial IgA antibody (EMA) in a second blood sample.
Those guidelines have not been adopted on this continent, however, so Chang’s group assessed the positive predictive value (PPV) of the North American tTG-IgA assay to identify histologic findings of celiac disease.
Another issue is the absence of a universal standard threshold across labs for a high antibody value. “Common assays used in North America differ in performance, and there are not many large multicenter studies looking at this issue. Hopefully, a standard will be developed in the near future. Before this serologic pathway can enter into our guidelines, this question needs to be addressed.”
Study Details
The multicenter retrospective study by Dr. Chang’s team looked at patients younger than 18 years from three pediatric hospitals in Canada and nine in the US who had an elevated tTG-IgA within 6 months of an esophagogastroduodenoscopy from January 2016 to December 2021. Biopsy-confirmed celiac disease was determined by the presence of intraepithelial lymphocytosis and villous atrophy. The primary outcomes were the PPV of an elevated tTG-IgA and a tTG-IgA at least 10 times the upper limit of normal (10x ULN).
The study cohort included 4019 children (63.3% female, 9% with type 1 diabetes, and 2% with Down syndrome). Histologic findings were consistent with celiac disease for 3321 children, for a PPV of 82.6% (95% CI, 81.4%-83.8%).
Among the 1739 (43.2%) children with tTG-IgA of at least 10x ULN, 1651 had biopsy-confirmed celiac disease, for a PPV 10x ULN of 94.9% (95% CI, 93.8%-95.9%). About 5% (n = 88) of positive-testing children did not have histologic findings of celiac disease, including 2% (n = 41) with normal histology.
Diagnostic accuracy of tTG-IgA varied widely among the assays used in North America, with a PPV range of 71.5%-88.8% and a PPV 10x ULN range of 89.3%-97.3%. Assays did not perform as well in children with type 1 diabetes: PPV 10x ULN of 89% (95% CI, 83.5%-92.8%).
In other notable findings, the EMA blood test only marginally improved specificity, as 76% of children without celiac disease, but with a tTG-IgA of at least 10x ULN had a positive EMA in the same sample.
While the study lends credence to the notion that a highly positive tTG-IgA correlates with enteropathy in most children, the 1 in 20 with a tTG-IgA greater than 10x ULN who did not have histologic findings diagnostic of celiac disease cannot be ignored. “This included 2% who had normal small intestinal biopsies on a gluten-containing unrestricted diet, highlighting the limitations of making a celiac disease diagnosis based solely upon a single, highly positive tTG-IgA level,” Chang and colleagues wrote.
Does this mean that substantial numbers of children with suspected celiac disease are being unnecessarily placed on gluten-restricted diets to no avail? “That’s a good question, but our retrospective data do not provide an answer to that,” Chang said. And what causes elevated autoantibodies in children who are not diagnosed with celiac disease? “That is also a question that will require further research,” he said.
Commenting on the study but not involved in it, Supriya Nair, MD, a pediatric gastroenterologist at UTHealth Houston, called it “very interesting because it highlights for primary care physicians that we may need endoscopic evaluation more than we thought.” This is particularly true given the lack of standardized laboratory values noted in the study.
Nair said that some children with high seromarker levels but no discernible lesions may develop celiac disease later. “It may be that the markers are not yet causing inflammation in the bowel. These patients must be monitored to see if levels stay high or come down.”
In her practice, she has seen some children who have been put on gluten-free diets prematurely. “But it’s very important to get an accurate, official confirmation with endoscopy because of the ramifications of a celiac diagnosis,” she said. “This is a lifelong condition, and the diet is not easy to follow, especially in North America.” And for children, especially, there are restrictive social impacts and the constant need to be aware of what they’re eating and the danger of cross-contamination in foods, she said.
Chang hopes these data will be pivotal in helping medical societies develop new North American guidelines. In the meantime, pediatricians and primary doctors need to be aware that a high number on a tTG-IgA test does not always mean the presence of celiac disease, although it could be a harbinger of its future development. “Further confirmation by a specialist is essential.”
The study was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health. Chang and Nair reported having no competing interests. Several study authors reported receiving research support from and serving as consultants or members of data safety monitoring boards for pharmaceutical companies.
A version of this article appeared on Medscape.com.
, a large pediatric cohort study in North America found.
Because tTG-IgA assay performance varied widely across labs, diagnostic confirmation by a specialist is essential before gluten-targeted dietary changes are made, according to Denis Chang, MD, MS, of the Division of Gastroenterology and Nutrition at Boston Children’s Hospital in Boston, and colleagues reported in Pediatrics.
“Currently, small intestinal biopsy is the gold standard for diagnosing pediatric celiac disease, but recent European diagnostic criteria allow a nonbiopsy pathway for serologic diagnosis,” Chang told GI & Heaptology News. The European guidelines allow this pathway when a very high tTG-IgA is confirmed by a positive endomysial IgA antibody (EMA) in a second blood sample.
Those guidelines have not been adopted on this continent, however, so Chang’s group assessed the positive predictive value (PPV) of the North American tTG-IgA assay to identify histologic findings of celiac disease.
Another issue is the absence of a universal standard threshold across labs for a high antibody value. “Common assays used in North America differ in performance, and there are not many large multicenter studies looking at this issue. Hopefully, a standard will be developed in the near future. Before this serologic pathway can enter into our guidelines, this question needs to be addressed.”
Study Details
The multicenter retrospective study by Dr. Chang’s team looked at patients younger than 18 years from three pediatric hospitals in Canada and nine in the US who had an elevated tTG-IgA within 6 months of an esophagogastroduodenoscopy from January 2016 to December 2021. Biopsy-confirmed celiac disease was determined by the presence of intraepithelial lymphocytosis and villous atrophy. The primary outcomes were the PPV of an elevated tTG-IgA and a tTG-IgA at least 10 times the upper limit of normal (10x ULN).
The study cohort included 4019 children (63.3% female, 9% with type 1 diabetes, and 2% with Down syndrome). Histologic findings were consistent with celiac disease for 3321 children, for a PPV of 82.6% (95% CI, 81.4%-83.8%).
Among the 1739 (43.2%) children with tTG-IgA of at least 10x ULN, 1651 had biopsy-confirmed celiac disease, for a PPV 10x ULN of 94.9% (95% CI, 93.8%-95.9%). About 5% (n = 88) of positive-testing children did not have histologic findings of celiac disease, including 2% (n = 41) with normal histology.
Diagnostic accuracy of tTG-IgA varied widely among the assays used in North America, with a PPV range of 71.5%-88.8% and a PPV 10x ULN range of 89.3%-97.3%. Assays did not perform as well in children with type 1 diabetes: PPV 10x ULN of 89% (95% CI, 83.5%-92.8%).
In other notable findings, the EMA blood test only marginally improved specificity, as 76% of children without celiac disease, but with a tTG-IgA of at least 10x ULN had a positive EMA in the same sample.
While the study lends credence to the notion that a highly positive tTG-IgA correlates with enteropathy in most children, the 1 in 20 with a tTG-IgA greater than 10x ULN who did not have histologic findings diagnostic of celiac disease cannot be ignored. “This included 2% who had normal small intestinal biopsies on a gluten-containing unrestricted diet, highlighting the limitations of making a celiac disease diagnosis based solely upon a single, highly positive tTG-IgA level,” Chang and colleagues wrote.
Does this mean that substantial numbers of children with suspected celiac disease are being unnecessarily placed on gluten-restricted diets to no avail? “That’s a good question, but our retrospective data do not provide an answer to that,” Chang said. And what causes elevated autoantibodies in children who are not diagnosed with celiac disease? “That is also a question that will require further research,” he said.
Commenting on the study but not involved in it, Supriya Nair, MD, a pediatric gastroenterologist at UTHealth Houston, called it “very interesting because it highlights for primary care physicians that we may need endoscopic evaluation more than we thought.” This is particularly true given the lack of standardized laboratory values noted in the study.
Nair said that some children with high seromarker levels but no discernible lesions may develop celiac disease later. “It may be that the markers are not yet causing inflammation in the bowel. These patients must be monitored to see if levels stay high or come down.”
In her practice, she has seen some children who have been put on gluten-free diets prematurely. “But it’s very important to get an accurate, official confirmation with endoscopy because of the ramifications of a celiac diagnosis,” she said. “This is a lifelong condition, and the diet is not easy to follow, especially in North America.” And for children, especially, there are restrictive social impacts and the constant need to be aware of what they’re eating and the danger of cross-contamination in foods, she said.
Chang hopes these data will be pivotal in helping medical societies develop new North American guidelines. In the meantime, pediatricians and primary doctors need to be aware that a high number on a tTG-IgA test does not always mean the presence of celiac disease, although it could be a harbinger of its future development. “Further confirmation by a specialist is essential.”
The study was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health. Chang and Nair reported having no competing interests. Several study authors reported receiving research support from and serving as consultants or members of data safety monitoring boards for pharmaceutical companies.
A version of this article appeared on Medscape.com.