Background: This study was performed to define the clinical relevance of early changes of capillary 3beta-hydroxybutyrate (3betaOHB), for detection of metabolic deterioration before occurrence of overt diabetic ketoacidosis following interruption of continuous subcutaneous insulin infusion (CSII).
Methods: An open clinical trial was performed with eight patients with type 1 diabetes on CSII therapy. After an overnight fast, at 8 a.m. (T0) CSII was interrupted for 4 h. At noon (T240) CSII was re-established, and at 4 p.m. (T480) the study was ended. Blood glucose (BG) and capillary and plasma 3betaOHB were measured at 30-min intervals, plasma insulin at 60-min intervals, and urinary ketones at 120-min intervals.
Results: After CSII interruption mean BG increased from 149.8+/-54.4 mg/dL at T0 to 224.8+/-56.2 mg/dL at T240 (P<0.05), and mean capillary 3betaOHB increased from 0.1+/-0.1 mmol/L at T0 to 0.9+/-0.6 mmol/L at T240 (P<0.001). The rate of increase of capillary 3betaOHB was faster and significantly more relevant than that of BG (P<0.05). The restoration of CSII produced a significant reduction of mean BG and capillary 3betaOHB (T480, 119.5+/-24 mg/dL and 0.2+/-0.2 mmol/L, respectively; P<0.05 for both vs. T240). The recovery of capillary 3betaOHB was significantly faster than that of BG (P=0.03).
Conclusions: The dynamic evaluation of changes of capillary 3betaOHB levels can represent a useful support to home BG monitoring in the event of CSII interruption, providing faster information on early metabolic deterioration due to insulin deprivation and allowing preventative action for avoiding the evolution towards overt diabetic ketoacidosis. After reintroduction of insulin infusion the monitoring of the faster recovery of 3betaOHB relative to BG can provide useful information for the prevention of late hypoglycemia due to insulin overinfusion.