{"title":"难治性甲状腺功能减退患者的左甲状腺素吸收试验：如何解释患者对该试验的反应？","authors":"Ibtissem Oueslati, Ameni Terzi, Meriem Yazidi, Elyes Kamoun, Moncef Feki, Melika Chihaoui","doi":"10.1007/s12020-025-04312-w","DOIUrl":null,"url":null,"abstract":"<p><strong>Introduction: </strong>Levothyroxine (LT4) absorption test is indicated in patients with refractory hypothyroidism to distinguish between pseudo-malabsorption and malabsorption. However, this test is not standardized and its interpretation remains controversial. The aim of the present study was to evaluate the different interpretations of the LT4 absorption test to confirm or infirm a disorder of LT4 absorption in patients with refractory hypothyroidism.</p><p><strong>Methods: </strong>This was a retrospective study including patients who were admitted for refractory hypothyroidism. LT4 absorption test was performed in all patients. Four different equations were used to interpret the test: The LT4 absorption rate, FT4 increment, FT4 increase rate, and FT4 ratio. Celiac disease serology and digestive endoscopy with biopsy were performed in all patients.</p><p><strong>Results: </strong>Seven patients were enrolled in this study. Their median age was 38 years. The median duration of hypothyroidism was 2.6 years. The median dose of LT4 was 4 µg/kg/day. Before the LT4 absorption test, the median TSH and FT4 levels were 72.59 mIU/L and 0.52 ng/dL, respectively. Using LT4 absorption rate and FT4 ratio formulas, the test was consistent with the diagnosis of malabsorption in all patients. However, when using FT4 increase rate, four patients (P1, P2, P4, and P5) had malabsorption and three patients (P3, P6, and P7) had pseudo-malabsorption. According to the FT4 increment, six patients (P1, P2, P4, P5, P6, and P7) had malabsorption and one patient (P3) had pseudo-malabsorption. Etiological investigations revealed the presence of Helicobacter pylori gastritis in four patients (P1, P2, P4, and P5). Patients 3, 6, and 7 admitted non-compliance with LT4 treatment when confronted with evidence about pseudo-malabsorption.</p><p><strong>Conclusion: </strong>The FT4 increase rate seemed more effective than LT4 absorption rate, FT4 ratio, and FT4 increment in differentiating pseudo-malabsorption from malabsorption. However, further multicenter studies involving larger sample sizes would be useful to confirm these findings.</p>","PeriodicalId":49211,"journal":{"name":"Endocrine","volume":" ","pages":""},"PeriodicalIF":3.0000,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Levothyroxine absorption test in patients with refractory hypothyroidism: how to interpret patient's response to the test?\",\"authors\":\"Ibtissem Oueslati, Ameni Terzi, Meriem Yazidi, Elyes Kamoun, Moncef Feki, Melika Chihaoui\",\"doi\":\"10.1007/s12020-025-04312-w\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Introduction: </strong>Levothyroxine (LT4) absorption test is indicated in patients with refractory hypothyroidism to distinguish between pseudo-malabsorption and malabsorption. However, this test is not standardized and its interpretation remains controversial. The aim of the present study was to evaluate the different interpretations of the LT4 absorption test to confirm or infirm a disorder of LT4 absorption in patients with refractory hypothyroidism.</p><p><strong>Methods: </strong>This was a retrospective study including patients who were admitted for refractory hypothyroidism. LT4 absorption test was performed in all patients. Four different equations were used to interpret the test: The LT4 absorption rate, FT4 increment, FT4 increase rate, and FT4 ratio. Celiac disease serology and digestive endoscopy with biopsy were performed in all patients.</p><p><strong>Results: </strong>Seven patients were enrolled in this study. Their median age was 38 years. The median duration of hypothyroidism was 2.6 years. The median dose of LT4 was 4 µg/kg/day. Before the LT4 absorption test, the median TSH and FT4 levels were 72.59 mIU/L and 0.52 ng/dL, respectively. Using LT4 absorption rate and FT4 ratio formulas, the test was consistent with the diagnosis of malabsorption in all patients. However, when using FT4 increase rate, four patients (P1, P2, P4, and P5) had malabsorption and three patients (P3, P6, and P7) had pseudo-malabsorption. According to the FT4 increment, six patients (P1, P2, P4, P5, P6, and P7) had malabsorption and one patient (P3) had pseudo-malabsorption. Etiological investigations revealed the presence of Helicobacter pylori gastritis in four patients (P1, P2, P4, and P5). Patients 3, 6, and 7 admitted non-compliance with LT4 treatment when confronted with evidence about pseudo-malabsorption.</p><p><strong>Conclusion: </strong>The FT4 increase rate seemed more effective than LT4 absorption rate, FT4 ratio, and FT4 increment in differentiating pseudo-malabsorption from malabsorption. However, further multicenter studies involving larger sample sizes would be useful to confirm these findings.</p>\",\"PeriodicalId\":49211,\"journal\":{\"name\":\"Endocrine\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":3.0000,\"publicationDate\":\"2025-06-14\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Endocrine\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://doi.org/10.1007/s12020-025-04312-w\",\"RegionNum\":3,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENDOCRINOLOGY & METABOLISM\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Endocrine","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1007/s12020-025-04312-w","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENDOCRINOLOGY & METABOLISM","Score":null,"Total":0}
Levothyroxine absorption test in patients with refractory hypothyroidism: how to interpret patient's response to the test?
Introduction: Levothyroxine (LT4) absorption test is indicated in patients with refractory hypothyroidism to distinguish between pseudo-malabsorption and malabsorption. However, this test is not standardized and its interpretation remains controversial. The aim of the present study was to evaluate the different interpretations of the LT4 absorption test to confirm or infirm a disorder of LT4 absorption in patients with refractory hypothyroidism.
Methods: This was a retrospective study including patients who were admitted for refractory hypothyroidism. LT4 absorption test was performed in all patients. Four different equations were used to interpret the test: The LT4 absorption rate, FT4 increment, FT4 increase rate, and FT4 ratio. Celiac disease serology and digestive endoscopy with biopsy were performed in all patients.
Results: Seven patients were enrolled in this study. Their median age was 38 years. The median duration of hypothyroidism was 2.6 years. The median dose of LT4 was 4 µg/kg/day. Before the LT4 absorption test, the median TSH and FT4 levels were 72.59 mIU/L and 0.52 ng/dL, respectively. Using LT4 absorption rate and FT4 ratio formulas, the test was consistent with the diagnosis of malabsorption in all patients. However, when using FT4 increase rate, four patients (P1, P2, P4, and P5) had malabsorption and three patients (P3, P6, and P7) had pseudo-malabsorption. According to the FT4 increment, six patients (P1, P2, P4, P5, P6, and P7) had malabsorption and one patient (P3) had pseudo-malabsorption. Etiological investigations revealed the presence of Helicobacter pylori gastritis in four patients (P1, P2, P4, and P5). Patients 3, 6, and 7 admitted non-compliance with LT4 treatment when confronted with evidence about pseudo-malabsorption.
Conclusion: The FT4 increase rate seemed more effective than LT4 absorption rate, FT4 ratio, and FT4 increment in differentiating pseudo-malabsorption from malabsorption. However, further multicenter studies involving larger sample sizes would be useful to confirm these findings.
期刊介绍：
Well-established as a major journal in today’s rapidly advancing experimental and clinical research areas, Endocrine publishes original articles devoted to basic (including molecular, cellular and physiological studies), translational and clinical research in all the different fields of endocrinology and metabolism. Articles will be accepted based on peer-reviews, priority, and editorial decision. Invited reviews, mini-reviews and viewpoints on relevant pathophysiological and clinical topics, as well as Editorials on articles appearing in the Journal, are published. Unsolicited Editorials will be evaluated by the editorial team. Outcomes of scientific meetings, as well as guidelines and position statements, may be submitted. The Journal also considers special feature articles in the field of endocrine genetics and epigenetics, as well as articles devoted to novel methods and techniques in endocrinology.
Endocrine covers controversial, clinical endocrine issues. Meta-analyses on endocrine and metabolic topics are also accepted. Descriptions of single clinical cases and/or small patients studies are not published unless of exceptional interest. However, reports of novel imaging studies and endocrine side effects in single patients may be considered. Research letters and letters to the editor related or unrelated to recently published articles can be submitted.
Endocrine covers leading topics in endocrinology such as neuroendocrinology, pituitary and hypothalamic peptides, thyroid physiological and clinical aspects, bone and mineral metabolism and osteoporosis, obesity, lipid and energy metabolism and food intake control, insulin, Type 1 and Type 2 diabetes, hormones of male and female reproduction, adrenal diseases pediatric and geriatric endocrinology, endocrine hypertension and endocrine oncology.
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号
