High variability in oral glucose tolerance among 1,128 patients with cystic fibrosis: a multicenter screening study.
BACKGROUND
In cystic fibrosis, highly variable glucose tolerance is suspected. However, no study provided within-patient coefficients of variation. The main objective of this short report was to evaluate within-patient variability of oral glucose tolerance.


METHODS
In total, 4,643 standardized oral glucose tolerance tests of 1,128 cystic fibrosis patients (median age at first test: 15.5 [11.5; 21.5] years, 48.8% females) were studied. Patients included were clinically stable, non-pregnant, and had at least two oral glucose tolerance tests, with no prior lung transplantation or systemic steroid therapy. Transition frequency from any one test to the subsequent test was analyzed and within-patient coefficients of variation were calculated for fasting and two hour blood glucose values. All statistical analysis was implemented with SAS 9.4.


RESULTS
A diabetic glucose tolerance was confirmed in 41.2% by the subsequent test. A regression to normal glucose tolerance at the subsequent test was observed in 21.7% and to impaired fasting glucose, impaired glucose tolerance or both in 15.2%, 12.0% or 9.9%. The average within-patient coefficient of variation for fasting blood glucose was 11.1% and for two hour blood glucose 25.3%.


CONCLUSIONS
In the cystic fibrosis patients studied, a highly variable glucose tolerance was observed. Compared to the general population, variability of two hour blood glucose was 1.5 to 1.8-fold higher.
Institute of Epidemiology and Medical Biometry, Central Institute for Biomedical Technology, University of Ulm, Ulm, Germany.
Nicole
N
Scheuing
Institute of Epidemiology and Medical Biometry, Central Institute for Biomedical Technology, University of Ulm, Ulm, Germany.
Reinhard W
RW
Holl
Cystic Fibrosis Centre, Saarland University Hospital for Pediatric and Adolescent Medicine, Homburg/Saar, Germany.
Gerd
G
Dockter
Institute of Epidemiology and Medical Biometry, Central Institute for Biomedical Technology, University of Ulm, Ulm, Germany.
Julia M
JM
Hermann
Clinic for Pediatric Pneumology and Neonatology, Hannover Medical School, Hannover, Germany.
Sibylle
S
Junge
Department of Pediatric Pulmonology, St. Josef Hospital Pediatric Clinic, Ruhr University Bochum, Bochum, Germany.
Cordula
C
Koerner-Rettberg
Department of Pediatrics, Justus-Liebig University Giessen, Giessen, Germany.
Lutz
L
Naehrlich
Medical Clinic I, Pneumology and Allergology, University Hospital Frankfurt/Main, Goethe University, Frankfurt/Main, Germany.
Christina
C
Smaczny
Division of Pulmonology and Immunology, Department of Pediatrics, Charité Berlin, Berlin, Germany.
Doris
D
Staab
Department for Pediatric Pulmonology and Allergology, Medical University of Graz, Graz, Austria.
Gabriela
G
Thalhammer
Cystic Fibrosis Centre Cologne, Childrens Hospital, University of Cologne, Cologne, Germany.
Silke
S
van Koningsbruggen-Rietschel
Department of Pediatric Pulmonology, St. Josef Hospital Pediatric Clinic, Ruhr University Bochum, Bochum, Germany.
Manfred
M
Ballmann
D000293:Adolescent; D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D003550:Cystic Fibrosis / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D048909:Diabetes Complications; D003920:Diabetes Mellitus / Q000097:blood* / Q000503:physiopathology; D005215:Fasting; D005260:Female; D018149:Glucose Intolerance / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D005951:Glucose Tolerance Test; D006801:Humans; D008297:Male; D055815:Young Adult
D001786:Blood Glucose