Achievement of cholesterol targets and prescribing of higher-cost statins: a cross-sectional study in general practice

Background

There is conflicting evidence as to whether achievement of cholesterol targets at the population level is dependent on the choice and cost of statin.

Aim

To investigate the practice-level relationship between cholesterol quality indicators in patients with heart disease, stroke, and diabetes and prescribing of low-cost statins.

Design and setting

Correlations and linear regression modelling of retrospective cross-sectional practice-level data with potential explanatory variables in 7909 (96.4%) general practices in England in 2008–2009.

Method

Quality indicator data were obtained from the Information Centre and prescribing data from the NHS Business Authority. A ‘cholesterol quality indicator’ score was constructed by dividing the numbers of patients achieving the target for cholesterol control of ≤5 mmol/l in stroke, diabetes, and heart disease by the numbers on each register. A ‘low-cost statin’ ratio score was constructed by dividing the numbers of defined daily doses of simvastatin and pravastatin by the total numbers of defined daily doses of statins.

Results

Simvastatin accounted for 83.3% (standard deviation [SD] = 15.7%) of low-cost statins prescribed and atorvastatin accounted for 85.7% (SD = 14.8%) of high-cost statins prescribed. The mean cholesterol score was 73.7% (SD = 6.0%). Practices using a higher proportion of the low-cost statins were less successful in achieving cholesterol targets. An increase of 10% in the prescribing of low-cost statins was associated with a decrease of 0.46% in the cholesterol quality indicator score (95% confidence interval = –0.54% to –0.38%, P<0.001).

Conclusion

Greater use of low-cost statins was associated with a small reduction in cholesterol control.