The breath analysis (BreathSpec® device) data of all participants that were included into the VAARA study (NCT05771090) will be analysed, this includes data from up to 40 breath samples from each of the 10 participants who underwent 2 insulin-induced hypoglycaemic episodes during two visits. The primary objective is to find a possible association between volatile organic compounds (VOCs) measured by the BreathSpec® device and blood glucose. For this we will use descriptive statistics, correlation coefficients, as well as a Principal Component Analysis and a partial least squares discriminant analysis. Furthermore, the time lag between hypoglycaemia onset and change in VOCs will be quantified.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
10
Different induced glycaemic states in people living with diabetes (PwD).
University of Bern
Bern, Switzerland
Changes VOC Patterns over time as gallery plots
Difference in gallery plots (3D visualization of retention index, drift time, ion current) from selected VOC peaks over time.
Time frame: During the study procedure (approximately 5 hours)
Changes VOC Patterns over time as boxplots
Difference in box plots from selected VOC peaks over time.
Time frame: During the study procedure (approximately 5 hours)
Correlation between blood glucose and patterns
Signals will be classified into euglycemic (between 4 and 10 mmol/l), hypoglycaemic (smaller than 4 mmol/l) and hyperglycaemic (above 10 mmol/l) phases or stable and changing phases. A principal component analysis (PCA) of the data will be performed to identify which VOCs are characteristic for certain glucose levels. A partial least squares discriminant analysis (PLS-DA) will be used to further identify important features of the VOC fingerprints.
Time frame: During the study procedure (approximately 5 hours)
Time lag
The time lag between hypoglycaemia onset and change in VOCs will be calculated-
Time frame: During the study procedure (approximately 5 hours)
Association between the onset of change in glucose, vital signs and VOC spectra
Associations between changes in VOCs and perceived hypoglycaemic symptoms, heart rate, ECG, and oxygen saturation will be evaluated using correlation coefficients and mixed effects models.
Time frame: During the study procedure (approximately 5 hours)
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