Primary Care Trusts (PCTs) with a high proportion of simvastatin and pravastatin prescribing are just as successful at achieving Quality and Outcomes Framework (QOF) national cholesterol targets as those that used more atorvastatin, rosuvastatin or fluvastatin.
This study provides reassurance to prescribers that they should continue to follow recent NICE guidance on lipid modification and initiate lipid-lowering therapy with the statin with the lowest acquisition cost for both the primary and secondary prevention of cardiovascular disease (CVD). This involves prescribing simvastatin 40mg initially; and either reducing the dose or using pravastatin if there are potential drug interactions, or if simvastatin is contraindicated. For patients with type 2 diabetes, NICE guidance also recommends initiating treatment with generic simvastatin 40mg, or a statin of similar efficacy and cost.
What is the background to this?
The Quality and Outcomes Framework (QOF) rewards GP practices for measuring the cholesterol of people with coronary heart disease (CHD), stroke or transient ischaemic attack (TIA), or diabetes annually. It also rewards practices if the recorded total cholesterol of a large proportion of these people is 5 mmol/L or less. The NICE guidance on lipid modification also recommends 5 mmol/L as an audit standard for total cholesterol in people with established cardiovascular disease (CVD). No lipid level target or audit standard is given for people without established CVD (see previous blog). The NICE guidance on management of type 2 diabetes recommends annual cholesterol monitoring and a target total cholesterol of less than 4 mmol/L or an LDL-cholesterol of below 2mmol/L (see previous blog). Intensifying treatment (e.g. by increasing to simvastatin 80mg or adding ezetimibe▼) may be required for patients with type 2 diabetes with new or established CVD, or increased albumin excretion.
What is this study about?
This study, published in the Journal of Health Services Research and Policy, aimed to identify whether PCTs that used a high proportion of the cheaper generic statins, i.e. simvastatin and pravastatin, performed as well on the QOF national cholesterol targets as PCTs that used less. This was done by cross-referencing QOF data for 2005/2006 with prescribing data for the same year.
What does this study claim?
The study found no evidence of a statistically significant association between the use of simvastatin and pravastatin (measured as a percentage of all statin items) and success in achieving the QOF national cholesterol targets. The average achievement of the QOF indicators for CHD, stroke or TIA, and diabetes were 78% (range 66% to 88%), 72% (58% to 82%) and 79% (67% to 88%), respectively). The percentage use of simvastatin/pravastatin by PCTs varied from 18% to 84% with a mean value of 57%.
This study provides reassurance that prescribers can continue to prescribe cheaper generic statins, with simvastatin 40mg usually being first-choice. For individuals with established CVD, who do not have type 2 diabetes, increasing the dose of simvastatin to 80mg daily may be considered if a total cholesterol of less than 4mmol/L or an LDL-cholesterol of less than 2 mmol/L is not attained. However, whilst cholesterol targets may help to guide the treatment of individual patients, it is important to note that the NICE guidance on lipid modification sets no lipid targets which patients are expected to achieve.
Further study details
It should be noted that this study only describes statin use in secondary prevention of CVD and in diabetes (not primary prevention of CVD) and only looks at the relationship between statin use and QOF data over one year. We have highlighted in a previous blog that a single cholesterol level reading may under- or over-estimate a person’s true average cholesterol level by up to 14%. In addition, whilst it is possible that some patients’ data were not reported because they did not achieve the QOF target, such “exception reporting” was low in this study.