Insulin pumps may help stabilize glucose levels over the long term
medwireNews: Continuous subcutaneous insulin infusion (CSII) users have more stable glycated hemoglobin (HbA1c) levels over the long term than multiple daily injection (MDI) users with type 1 diabetes, a real-world study suggests.
Reporting in BMJ Open, the researchers say: “HbA1c variability, a simple and low cost measure, thought to modulate chronic diabetes complication risk, should be a routine tool to assess glycemic control in clinical practice and in clinical research and trials.”
They carried out an audit of 506 outpatient clinical records from two independent Australian tertiary referral diabetes centers. Long-term HbA1c variability was significantly lower in the 164 individuals treated with insulin pump therapy during a mean of 4.1 years than the 342 receiving MDI when assessed from the HbA1c standard deviation, at a corresponding 0.5% (6 mmol/mol) versus 0.7% (9 mmol/mol).
The same was true for the HbA1c coefficient of variation, at a corresponding 6.7% (10 mmol/mol) versus 9.3% (14 mmol/mol).
This occurred despite similar mean HbA1c levels, at 7.8% (62 mmol/mol) on CSII and 8.0% (64 mmol/mol) on MDI, and the insulin delivery modalities not, on the whole, involving real-time continuous glucose monitoring. Participants were a mean of 38 years of age and had lived with diabetes for a mean of 17 years.
The difference in glycemic variability remained statistically significant after adjusting for multiple potential confounding factors such as sex, hospital location, chronic complication status, baseline HbA1c, age, and socioeconomic status.
There was a similar pattern of HbA1c variability favoring CSII in women and men, in people aged 26 years and older as well as in younger patients, and it remained lower in CSII users across different thirds of mean HbA1c levels.
Glycemic variability was also significantly reduced among the 56 individuals who changed insulin delivery modality from MDI to CSII, but remained similar among those who continued on the daily injections.
Glycemic variation assessed from 1 year after changeover decreased significantly with a standard deviation of 0.7% (8 mmol/mol) pre-CSII versus 0.4% (5 mmol/mol) post-CSII and a coefficient of variation of 9.2% (13 mmol/mol) versus 6.1% (9 mmol/mol), respectively.
Alicia Jenkins (University of Sydney, New South Wales, Australia) and colleagues note that a previous study of theirs found comparable short-term glycemic variability with CSII and MDI.
Nonetheless, they add: “We speculate that lower HbA1c variability, as associated with CSII use in our study, may underpin or at least contribute to the observed reduced chronic complication and death rates among CSII users.”
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