Oral glucose tolerance test and continuous glucose monitoring to assess diabetes development in cystic fibrosis patients

Continuous glucose monitoring devices measure glucose in interstitial fluid. The devices are effective when used by patients with type 1 and 2 diabetes but are increasingly being used by researchers who are interested in the effects of various behaviours of glucose concentrations in healthy participants. Despite their more frequent application in this setting, the devices have not yet been validated for use under such conditions. A total of 124 healthy participants were recruited to a ten-day laboratory study. Each participant underwent four oral glucose tolerance tests, and a total of 3315 out of a possible 4960 paired samples were included in the final analysis. Bland–Altman plots and mean absolute relative differences were used to determine the agreement between the two methods. Bland–Altman analyses revealed that the continuous glucose monitoring devices had proportional bias (R = 0.028, p < 0.001) and a mean bias of −0.048 mmol/L, and device measurements were more variable as glucose concentrations increased. Ninety-nine per cent of paired values were in Zones A and B of the Parkes Error Grid plot, and there was an overall mean absolute relative difference of 16.2% (±15.8%). There was variability in the continuous glucose monitoring devices, and this variability was higher when glucose concentrations were higher. If researchers were to use continuous glucose monitoring devices to measure glucose concentrations during an oral glucose tolerance test in healthy participants, this variability would need to be considered.

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Applicability of continuous glucose monitoring to screen for cystic fibrosis-related diabetes onset and clinical impairment

10.22541/au.162473605.54812216/v1 ◽

2021 ◽

Author(s):

Mariana Zorron ◽

Fernando Marson ◽

André Morcillo ◽

Aline Gonçalves ◽

Mayra de Souza El Beck ◽

...

Keyword(s):

Body Mass Index ◽

Cystic Fibrosis ◽

Glucose Tolerance ◽

Body Mass ◽

Continuous Glucose Monitoring ◽

Glucose Tolerance Test ◽

Glucose Monitoring ◽

Tolerance Test ◽

Oral Glucose ◽

Oral Glucose Tolerance

Background and Objectives: Cystic fibrosis-related diabetes is the major comorbidity in cystic fibrosis and reduces life expectancy, highlighting the need for early diagnosis and treatment. This study aimed to verify whether abnormal continuous glucose monitoring results predict cystic fibrosis-related diabetes onset and/or a decline in the forced expiratory volume in the 1st second or body mass index of patients with cystic fibrosis. Methods: Thirty-nine patients with cystic fibrosis (age 10–19 years) were screened for cystic fibrosis-related diabetes using the oral glucose tolerance test. Patients without diabetes diagnose underwent 3 days of continuous glucose monitoring, spirometry and body mass index measurements and were reassessed at the end of the study with a second spirometry, body mass index evaluation and oral glucose tolerance test. Results: Thirty-four patients completed the follow-up (3.1±0.51 years). None of the study variables predicted cystic fibrosis-related diabetes progression or were associated with hypoglycemic events. Continuous glucose monitoring could detect glucose abnormalities not revealed in the oral glucose tolerance test. Patients with glucose level of >140 mg/dL on continuous glucose monitoring showed significantly lower body mass index z scores at both study initiation (-1.55±1.68 vs. -0.17±0.88; p-value=0.02) and completion (-1.65±1.55 vs. -0.42±1.08; p-value=0.039). Conclusions: Continuous glucose monitoring can identify glucose abnormalities not detected by oral glucose tolerance test that are related to early stage decreases in body mass index. However, it was ineffective in predicting the onset of diabetes in this cystic fibrosis population. Different diagnostic criteria for diabetes may be required for individuals with cystic fibrosis.

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255 Screening glucose disorders in cystic fibrosis: Continuous subcutaneous glucose monitoring compared to oral glucose tolerance test

Journal of Cystic Fibrosis ◽

10.1016/s1569-1993(13)60396-3 ◽

2013 ◽

Vol 12 ◽

pp. S113

Author(s):

M. Santalha ◽

T.F. Barbosa ◽

B. Amaral ◽

T. Borges ◽

L. Ribeiro ◽

...

Keyword(s):

Cystic Fibrosis ◽

Glucose Tolerance ◽

Oral Glucose Tolerance Test ◽

Glucose Tolerance Test ◽

Glucose Monitoring ◽

Tolerance Test ◽

Oral Glucose ◽

Oral Glucose Tolerance

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Continuous glucose monitoring to evaluate glycaemic abnormalities in cystic fibrosis

Archives of Disease in Childhood ◽

10.1136/archdischild-2017-314250 ◽

2018 ◽

Vol 103 (6) ◽

pp. 592-596 ◽

Cited By ~ 3

Author(s):

Mariana Zorrón Mei Hsia Pu ◽

Aline Cristina Gonçalves ◽

Walter José Minnicucci ◽

André Moreno Morcillo ◽

José Dirceu Ribeiro ◽

...

Keyword(s):

Cystic Fibrosis ◽

Glucose Tolerance ◽

Oral Glucose Tolerance Test ◽

Glucose Tolerance Test ◽

Glucose Monitoring ◽

Tolerance Test ◽

Oral Glucose ◽

Test Results ◽

Oral Glucose Tolerance ◽

Interstitial Glucose

ObjectiveThis study aimed to determine the glycaemic profile of patients with cystic fibrosis using a continuous glucose monitoring system (CGMS), and to evaluate the associations of glycaemic abnormalities with sex, age, pubertal stage, CFTR gene mutations, nutritional status, lung function, oral glucose tolerance test, glycated haemoglobin concentrations, fasting insulin concentrations, C peptide concentrations and exocrine pancreatic function.Study designThis observational study evaluated CGMS data from 39 patients with cystic fibrosis who were treated at a referral centre. The patients were 10–19.9 years old, and were categorised according to whether they had normal results (27 patients) or glucose intolerance (12 patients) during the oral glucose tolerance test.ResultsThe maximum interstitial glucose concentration among individuals with normal oral glucose tolerance test results was 174.9±65.1 mg/dL (9.7–3.61 mmol/L), compared with 170.4±40.9 mg/dL (9.46–2.27 mmol/L) among individuals with glucose intolerance. The CGMS revealed that 18 of the 27 patients with normal oral glucose tolerance test results had peak interstitial glucose concentrations of >140 mg/dL (7.8 mmol/L), and that 4 of these individuals had peak levels of >200 mg/dL (11.1 mmol/L). None of the analysed clinical or laboratory characteristics predicted the occurrence of hyperglycaemic peaks on CGMS.ConclusionsThe present study revealed that CGMS could detect hyperglycaemia among patients with cystic fibrosis and ‘normal’ oral glucose tolerance test results, and that their clinical and laboratory characteristics were not useful in discerning between patients who did and did not exhibit these excursions.

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