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Evid Based Nurs 11:52 doi:10.1136/ebn.11.2.52
  • Treatment

Primary prevention with pravastatin for 5 years continued to prevent coronary events in the next 10 years

I Ford

Dr I Ford, University of Glasgow, Glasgow, UK; ian{at}stats.gla.ac.uk

QUESTION

In middle-aged men with hypercholesterolaemia and no history of myocardial infarction (MI), does 5 years of treatment with pravastatin have long-term benefits for prevention of coronary heart disease (CHD)?

METHODS

Design:

post-trial follow-up of a randomised, placebo-controlled trial (West of Scotland Coronary Prevention Study [WOSCOPS]).

Allocation:

unclear allocation concealment.

Blinding:

blinded during the trial period {clinicians, patients, data collectors, and outcome adjudication committees}.*

Follow-up period:

original trial follow-up was 5 years; this study followed up surviving patients (96%) for 10 more years.

Setting:

{coronary screening clinics in the UK}.*

Patients:

6595 men {45–64 years of age}* (mean age 55 y) with no history of MI and low-density lipoprotein cholesterol concentrations ⩾155 mg/dl (4.01 mmol/l) on 2 occasions.

Intervention:

pravastatin, 40 mg daily (n = 3302), or placebo (n = 3293) for 5 years. At the end of the trial, {70% of men in each group}* were still taking the study drug. After this time, statin treatment was at the discretion of each man’s physician.

Outcomes:

death from any cause, CHD, or cancer; CHD-related death or MI; CHD-related death or hospital admission; stroke; and cancer.

Patient follow-up:

100% (intention-to-treat analysis).

MAIN RESULTS

At 5 years after the end of the trial, 39% of men in the pravastatin group and 35% in the placebo group were receiving statin therapy (p<0.001). Results in the post-trial period are shown in the table, including sustained relative risk reductions in cardiovascular events for the total follow-up period. Groups did not differ during any period for overall incidence of stroke, cancer, or death from cancer.

Pravastatin v placebo for 5 years for primary prevention of coronary heart disease (CHD) in middle-aged men with hypercholesterolaemia*

CONCLUSION

In middle-aged men with hypercholesterolaemia and no history of myocardial infarction, 5 years of treatment with pravastatin continued to prevent coronary heart disease events in the following 10 years.

*Shepherd J, Cobbe SM, Ford I, et al. N Engl J Med 1995;333:1301–7.

A modified version of this abstract appears in ACP Journal Club.

ABSTRACTED FROM

Ford I, Murray H, Packard CJ, et al. Long-term follow-up of the West of Scotland Coronary Prevention Study. N Engl J Med 2007;357:1477–86.

Clinical impact ratings: Cardiology 7/7; Family/General practice 5/7

Footnotes

  • Source of funding: Chief Scientist Office of the Scottish Executive Health Department, Bristol-Myers Squibb, and Sankyo.

Commentary

In their 10-year follow-up study, Ford et al showed the long-term benefit of statins for primary prevention of CHD. Coronary events were reduced among patients who had originally received statin treatment, even though most did not continue to take statins in the post-trial period and some men in the original placebo group started statin treatment. Ford et al suggested that the likely mechanism of action of statins is the slowing of the progression of coronary artery disease. Long-term benefits of statin use also have been shown in secondary prevention trials.1 2 In these trials, >80% of patients in both the statin and placebo groups received cholesterol-lowering agents after the trial ended, but patients in the original statin groups had lower all-cause and CHD mortality at extended follow-up. Previous placebo-controlled trials of statin use for primary prevention showed medium-term benefits, but participants were followed up for ⩽5 years.3 4

Generalisability of the WOSCOPS results is restricted because only men 45–64 years of age from a limited geographical region were eligible. Although the maximum ages for participants in AFCAPS3 and ASCOT-LLA4 were higher (73 and 79 y, respectively), separate survival data for the older age groups were not given. Women were not included in WOSCOPS and comprised <20% of participants in all other trials (postmenopausal women only). A cautionary note: statins are being used in older people and both premenopausal and postmenopausal women despite the fact that their efficacy for primary prevention and long-term benefits are unknown in these populations.

References

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