medwireNews: Researchers have identified factors that predict repeated very low blood sugar among adults with type 1 diabetes who have suboptimal awareness of hypoglycemia.
In a pre-planned extended analysis of the HypoCOMPaSS trial, they found that severe hypoglycemia, in which blood glucose levels fell to 3.0 mmol/L or less, was associated with more frequent pre-study severe hypoglycemia, a fear of hypoglycemia, and concomitant neuropathy.
The multicenter trial was originally designed to compare different forms of insulin delivery and monitoring among patients with type 1 diabetes who had impaired awareness of hypoglycemia.
In the current analysis, James Shaw (Newcastle University, UK) and colleagues followed up 71 (81%) participants who experienced severe hypoglycemia in the pre-trial year to examine factors predicting an incomplete response, defined as at least one further severe hypoglycemic event over the 2-year period.
They identified 43 (61%) complete responders, who had no severe hypoglycemia during the 24-month follow-up, and 28 (39%) incomplete responders.
The two groups were similar in terms of intervention arm allocation (conventional subcutaneous insulin infusion vs multiple daily injections and continuous vs conventional glucose self-monitoring) and the numbers switching between treatment groups during the trial and follow-up.
Incomplete responders had a higher mean number of severe hypoglycemic events in the year prior to the trial compared with responders, at 16.9 versus 6.4 events per person–year.
But during follow-up, the number of severe hypoglycemic events experienced by incomplete responders reduced by 91% to a mean of 1.5 events per person–year.
Seven-day blinded continuous glucose monitoring before the 24-month follow-up visit revealed that incomplete and complete responders did not spend significantly different amounts of time with glucose levels of 3 mmol/L or less, at 1.4% versus 3.0%, respectively.
However, incomplete responders were more likely to have unresolved impaired hypoglycemia awareness, with 62% having a Clarke questionnaire score of at least 4 versus 29% of complete responders. They also scored higher on the Hypoglycemia Fear Survey II, at a corresponding 53.9 points versus 34.0 points.
Peripheral neuropathy was more than eight times more common among incomplete than complete responders, at a corresponding 39.3% versus 4.7%, with a trend toward more autonomic neuropathy.
Interestingly, baseline total daily insulin doses were comparable between the two responder groups, but were significantly lower among incomplete than complete responders at 24 months, at 0.45 versus 0.58 units/kg over 24 hours, respectively.
Reporting in Diabetes Care, the researchers maintain: “This supports appropriate insulin reduction to avoid biochemical hypoglycemia – as opposed to persistence with inappropriately high doses due to a strong preference for hypoglycemia over hyperglycemia.”
By Anita Chakraverty
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