Australian research that found people with type 2 diabetes put on an average of 3kg within the first year after starting insulin should serve as a wake up call, an expert says.

The prospective study published in the Internal Medicine Journal found the majority of the 340 patients with type 2 diabetes attending a tertiary hospital diabetes clinic gained weight – an average of 3kgs over the first year, and just over 25% gained more than 7% of their initial body weight.

“It’s a wake-up call”, leading researcher Dr John Wentworth, an endocrinologist at Royal Melbourne Hospital, told the limbic.

“This is a problem we need to look at, so we can work out what do about it,” he said.

Factors associated with weight gain were higher insulin doses, the use of short-acting insulin and a lower baseline body weight.

Clinically significant weight gain was associated with the use of short-acting insulin and thiazolidinediones whereas the concomitant use of other oral agents, particularly sulphonylureas, was associated with less weight gain.

However the combination of baseline insulin dose, body weight and insulin regimen only accounted for 10% of the variance in weight gain.

This finding pointed to the need for further research to help predict which patients are likely to gain weight, Dr Wentworth said.

The authors suggested that weight gain might be prevented or reduced by using a combination of oral agents with long-acting insulin, and starting with a smaller dose that is titrated to achieve a gradual reduction in HbA1c.

In a finding consistent with the UKPDS study insulin induced weight gain had no impact on cardiovascular risk factors, and weight gain did not cause blood pressure or lipids to rise.

“So perhaps weight gain isn’t such a big deal,” Dr Wentworth said.

The mean age of the study population was 64 years and mean duration of diabetes 13 years.

In the study 26% of participants used insulin alone, 71% used a combination of insulin and metformin and/or sulphonylureas, while the remaining 3% were using other agents in combination with insulin. HbA1c levels improved from 9.4% to 8.1% with insulin therapy.