"Understanding the pattern of insulin use is limited by a lack of data characterising the prevalence of insulin use in the UK," according to Craig Currie, Professor of Applied Pharmacoepidemiology at Cardiff University's School of Medicine, who led the study alongside colleagues from the University of Bristol.
"Given the limitations, our study sought to calculate – for the first time – the best possible estimate of the rates of insulin for type 1 and type 2 diabetes."
In this retrospective study the team examined the number of patients receiving prescriptions for insulin between 1991 and 2010.
The study found that the number of people using insulin trebled between 1991 and 2010, largely due to a large increase in the number of people with type 2 diabetes using the drug.
It estimates that the number of insulin users in the UK increased from 136,800 in 1991 to 421,300 in 2010.
The study also found that the number of people receiving prescriptions for insulin for type 2 diabetes during the period, overtook the number of people with type 1 diabetes.
In 1991, more people using insulin had type 1 diabetes than had type 2 diabetes however, by 2010 this situation had reversed with the total number of people with type 2 diabetes injecting insulin increased from 37,000 in 1991 to 277,400 in 2010.
Professor Currie adds: "As a result of the study, we found that the number of people injecting insulin in the UK increased three-fold over the 20-year period from 1991 to 2010.
"Also during this period there was more than a seven-fold increase in the number of those with a diagnosis of type 2 diabetes and treated with insulin. Most of this is unrelated to clinical need. Insulin is very expensive and some of us believe that it involves too many serious side effects in people with type 2 diabetes."
Whilst the study strikes a note of caution with its findings, most notably with early stages of the timescales of the reporting being less well recorded, the study does give a clear indication that the number of people with type 2 diabetes using insulin has risen sharply.
"The rising prevalence of insulin use probably reflects both an increase in incidence and longer survival of those who already have type 2 diabetes. The financial cost of insulin to the NHS in the UK is estimated to have increased from £156M in 2000 to £359M in 2009.
"The increase in the number of people with type 2 diabetes using insulin is a wake-up call for all – not only in terms of lifestyle choices and how we treat people with type 2 diabetes," Professor Currie adds.