Keele Research Repository

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Background
The use of statins has increased substantially over the last 2 decades in England and represents a significant cost burden to the National Health Service. Therefore, it is important to understand what influences prescribers' choice.

Objectives
This study examines the changes in use pattern of all statins in England (1998‐2015). The study focuses on the use of simvastatin and atorvastatin before and after their patent expiry and rosuvastatin, to investigate the impact of the reduced acquisition costs on prescribing.

Methods
Interrupted time series analysis of primary care use data from the health and social care information centre database from 1998 to 2015.

Results
Primary care expenditure on statins increased by 125% during the period 1998 to 2004 driven by branded simvastatin and atorvastatin. Before 2003, the rate of use of more potent branded atorvastatin exceeds branded simvastatin. Between 2004 and 2011, the less potent but less expensive agent generic simvastatin has the higher utilisation rate (66%). Since 2012, the more potent agent but less expensive generic atorvastatin has the higher utilisation rate (50%). The more potent branded rosuvastatin failed to make a significant impact on the English statins market.

Conclusions
The availability of generic statins has reduced overall expenditure significantly. When there is a significant price difference, acquisition cost appears to be the main influencing factor in prescribing statins, but, when costs are similar, potency is a key factor. This suggests that English prescribers are cost sensitive and appear to be prepared to trade marginal benefit for savings.