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Hemoglobin A1 and pancreatic beta cell function in cystic fibrosis
Insights
Children with cystic fibrosis (CF) show higher Hemoglobin A1 (HbA1) levels and decreased insulin response. Serial HbA1 monitoring may help detect worsening glucose tolerance in CF patients.
Area of Science:
- Pediatrics
- Endocrinology
- Genetics
Background:
- Cystic Fibrosis (CF) is a genetic disorder affecting multiple organs.
- Glucose metabolism and insulin secretion can be impaired in CF patients.
- Hemoglobin A1 (HbA1) reflects average blood glucose levels over time.
Purpose of the Study:
- To investigate Hemoglobin A1 (HbA1) blood levels in pediatric cystic fibrosis (CF) patients.
- To assess glucose tolerance and insulin response in CF patients.
- To determine the correlation between HbA1 levels and clinical status in CF.
Main Methods:
- Measured HbA1 levels in 34 CF patients (ages 1.5-20.5 years) and compared to 150 normal children.
- Performed oral glucose tolerance tests (OGTT) on 11 CF patients.
- Measured blood glucose and insulin concentrations during OGTT.
Main Results:
- CF patients had significantly higher mean HbA1 levels (7.97%) compared to normal children (6.8%).
- No difference in fasting blood glucose was observed.
- Three out of 11 CF patients showed impaired OGTT with delayed insulin response; all CF patients exhibited decreased insulin response.
- No correlation found between HbA1 and patient age or clinical status (Shwachman score).
Conclusions:
- Insulinopenia in pediatric CF patients is not always reflected by elevated HbA1.
- Serial HbA1 measurements may indicate deteriorating glucose tolerance in CF.
- Further investigation into glucose metabolism abnormalities in CF is warranted.
Abstract:
Hemoglobin A1 (HbA1) blood levels were examined in 34 cystic fibrosis (CF) patients aged 1 1/2 to 20 1/2 yr. The mean (+/- SD) HbA1 concentration in the 34 patients was 7.97 +/- 1.16--significantly higher than that in 150 normal children (6.8 +/- 0.8). Oral glucose tolerance tests (OGTT) were performed in 11 patients and blood glucose and insulin concentrations were measured. There was no difference in the fasting blood glucose values between the two groups. Eight children had a normal OGTT, and three showed an impaired OGTT with a delayed peak response in insulin levels. There was a decreased insulin response in all the CF patients. No correlation was found between HbA1 concentration and the age of the patients, nor between HbA1 and the clinical status (Shwachman score). We conclude that insulinopenia in children with CF is not always accompanied by an increment in HbA1, although serial determinations of its level may reveal deterioration in glucose tolerance.