Researchers say long-acting insulin significantly improves haemoglobin A1C levels, a measure of effective blood sugar control.

Long-acting insulin is safer and more effective than intermediate-acting insulin for patients with Type 1 diabetes, according to research.

Scientists looked at once-daily and twice-daily doses of both long- and intermediate-acting insulin, ranking their efficacy, safety and cost-effectiveness.

"In patients with Type 1 diabetes, we found that long-acting insulin is superior to intermediate-acting insulin when it came to controlling blood sugar, preventing weight gain and treating severe hypoglycaemia," said Dr Andrea
Tricco, the lead author of the paper and a scientist in the Li Ka Shing Knowledge Institute of St Michael's Hospital, Toronto.

Using data from 39 studies, Dr Tricco and her colleagues compared two long-acting forms of insulin - glargine and detemir - against intermediate-acting forms, such as Neutral Protamine Hagedorn (NPH).

Long-acting insulin takes about one hour after ingesting to begin lowering blood sugar and lasts up to 26 hours, while intermediate-acting insulin takes between one and three hours to begin lowering blood sugar and can last up to 16 hours.

Compared to intermediate-acting NPH, long-acting insulin significantly improved haemoglobin A1C levels, a measure of effective blood sugar control over time.

"Those taking intermediate-acting insulin were more likely to gain weight," Dr Tricco said.

"They gained an average of four to six pounds more than the participants who took most long-acting insulin doses."

Severe hypoglycaemia, when someone has extremely low blood sugar, is a medical emergency where the individual is unable to treat themselves and needs someone else to provide them with sugar quickly through food or via intravenous fluids.

The researchers found that people with Type 1 diabetes were 38 per cent less likely to experience severe hypoglycaemia, on average.

Dr Tricco also assessed the cost-effectiveness of the two types of insulin.

Of the 32 studies included in the review, there were 22 analyses evaluating the economic benefits of long- and intermediate-acting insulin.

About 77 per cent of those economic analyses found that long-acting insulin was more expensive, but also more effective than intermediate-acting insulin, while around 23 per cent found long-acting insulin more cost-effective.

"With this information, patients and their doctors should tailor their choice of insulin according to preference, cost and accessibility," said Dr Tricco.

The research was funded by the Drug Safety and Effectiveness Network of the Canadian Institutes of Health Research and is published in the BMJ.

Copyright AAP 2014.