How many people inject insulin? UK estimates from 1991 to 2010.

Aims: We set out to estimate the prevalence rate of insulin use in the UK population, the total number of people in the UK who use insulin, the proportion of users with type 1 and type 2 diabetes and changes between 1991 and 2010.

Methods: Patients receiving prescriptions for insulin were identified in the Clinical Practice Research Datalink and attributed a diagnosis of type 1 or type 2 diabetes. The annual prevalence of insulin use was calculated and applied to population data.

Results: The crude prevalence rate of insulin use increased from 2.43 (95% CI 2.38-2.49) per 1000 population in 1991 to 6.71 (6.64-6.77) per 1000 in 2010. The largest change was an increase in the prevalence of insulin users with a diagnosis of type 2 diabetes from 0.67 (0.64-0.70) to 4.34 (4.29-4.39) per 1000 population. The absolute number using insulin increased from 137 000 people (121 000-155 000) in 1991 to 421 000 (400 000-444 000) in 2010. The proportion taking insulin alone (as against combination with oral agents) decreased from 97% in the first decade to 37% in the second.

Conclusion: The number of people using insulin trebled between 1991 and 2010, largely due to a considerable increase in the number of people with type 2 diabetes using insulin.