Archief Roodbont

Discussion

In the UK, NICE seeks to guide clinicians towards clinically effective and economic choices for patient management. The NICE guidance (May 2008) on lipid modification recommends simvastatin 80 mg for secondary prevention and highlights the cost difference between a year's treatment with simvastatin 80 mg (£64.53) compared with atorvastatin 80 mg (£364.67) (9). According to the September 2010 British National Formulary, the cost difference has remained relatively unchanged, with a year's treatment with simvastatin 80 mg now costing £35.28 compared with £338.52 for atorvastatin 80 mg. However, atorvastatin is supported by more robust evidence at this dosage, particularly for secondary prevention (10,11). When atorvastatin comes off patent in the next few years, the cost difference between these medications will be significantly reduced. Until then, clinicians are faced with a conflict between prescribing for cost or for proven efficacy. This conflict is particularly challenging for clinicians treating high-risk patients, for whom the results of further cardiovascular events, loss of earnings and potential disability also have significant adverse economic effects, which may justify using a more expensive preventative agent. Unfortunately, there are no head-to-head randomised controlled studies comparing high intensity atorvastatin and simvastatin. In addition, there is little evidence about the relative merits of these agents in the setting of current clinical practice.

This study offers some comparison of high intensity atorvastatin with simvastatin in current clinical practice. Prescribers may find this 'real-life' approach useful when large-scale clinical evidence is lacking and clinical guidelines are conflicting. This audit suggests that high intensity atorvastatin is used in primary care, despite national guidelines that specifically recommend simvastatin use.^[9] In this study, patients on atorvastatin were less likely to fail to meet targets of cholesterol and LDL-C control when compared with simvastatin. This finding is consistent with other evidence supporting the efficacy of atorvastatin.^[7,10,11]

There are several limitations to this study. Importantly, it is a retrospective study with no blinding or randomisation of treatment groups. There were very few baseline lipid results available, which limits any comparison of relative efficacy of these medications on the basis of current lipid values. This outcome is because many patients had received statin treatment in some form for over a decade, predating notation in current records. However, the comparison of these agents, based on the need to discontinue therapy because of target failure remains valid, although may be affected by differences of prescribing behaviour and risk perception among prescribers. On data analysis, no statistically significant difference among prescribing behaviour and treatment effects was detected between the two general practitioners' surgeries.

A further limitation to this study involves the significantly increased usage of other lipid-lowering treatments in the atorvastatin group (p = 0.002). One must interpret the lipid concentrations with caution in light of this confounding factor, and regarding the absence of pre-treatment lipid values.

There has been recent concern about increased incidence of myositis and rhabdomyolysis in patients receiving simvastatin 80 mg.^[13,14] This study did not identify any patients with myositis or rhabdomyolysis in either treatment group. Interestingly, CK was checked in a minority of patients only. There was no statistically significant difference in tolerability between the two treatment groups. Current guidance suggests that patients with muscle-related symptoms on a statin should have CK checked.^[9]

In summary, this retrospective observational study describes routine clinical practice and highlights the conflict that prescribers face with regard to high-intensity statin use. Clinical trial evidence favours atorvastatin, whereas simvastatin remains the economic option and is favoured by national guidelines. Patients receiving atorvastatin 80 mg were significantly more likely to remain on the medication, achieving adequate cholesterol and LDL-C control, with no increase in intolerance when compared with patients treated with simvastatin 80 mg.