Long-Term Follow-up of the West of Scotland Coronary Prevention Study

Long-Term Follow-up of the West of Scotland Coronary Prevention Study




Ford I et al. for the West of Scotland Coronary Prevention Study Group. Long-term follow-up of the West of Scotland Coronary Prevention Study.


N Engl J Med 2007 Oct 11; 357:1477.


ABSTRACT


Background The West of Scotland Coronary Prevention Study was a randomized clinical trial comparing pravastatin with placebo in men with hypercholesterolemia who did not have a history of myocardial infarction, with an average follow-up of approximately 5 years. The combined outcome of death from definite coronary heart disease or definite nonfatal myocardial infarction was reduced from 7.9 to 5.5% (P<0.001) in the treatment group. Extended follow-up data were obtained for approximately 10 years after completion of the trial.


Methods For the survivors of the trial, all deaths, hospitalizations and deaths due to coronary events and stroke, and incident cancers and deaths from cancer were tracked with the use of a national computerized record-linkage system. The results were analyzed with time-to-event analyses and use of Cox proportional-hazards models.


Results Five years after the trial ended, 38.7% of the original statin group and 35.2% of the original placebo group were being treated with a statin. In the period approximately 10 years after completion of the trial, the risk of death from coronary heart disease or nonfatal myocardial infarction was 10.3% in the placebo group and 8.6% in the pravastatin group (P=0.02); over the entire follow-up period, the rate was 15.5% in the placebo group and 11.8% in the pravastatin group (P<0.001). Similar percentage reductions were seen in the combined rate of death from coronary heart disease and hospitalization for coronary events for both periods. The rate of death from cardiovascular causes was reduced (P=0.01), as was the rate of death from any cause (P=0.03), over the entire follow-up period. There were no excess deaths from noncardiovascular causes or excess fatal or incident cancers.



Conclusions In this analysis, 5 years of treatment with pravastatin was associated with a significant reduction in coronary events for a subsequent 10 years in men with hypercholesterolemia who did not have a history of myocardial infarction.




The West of Scotland Coronary Prevention Study: Long-Term Results


Published in Journal Watch Cardiology October 10, 2007


The benefits of statins for primary prevention of coronary heart disease stand the test of time.



Results published in 1995 from the West of Scotland Coronary Prevention Study (WOSCOPS), a randomized, double-blind, placebo-controlled clinical trial of pravastatin in middle-aged men without a history of MI, demonstrated a significant benefit after approximately 5 years of treatment (Journal Watch Cardiology Dec 1 1995). Now, the WOSCOPS investigators report outcomes over the subsequent 10 years.


About one third of the study subjects took statins during the post-trial period; the percentages were slightly higher in those who were originally randomized to pravastatin. During follow-up (mean, 13.2 years for cancer and 14.7 years for other outcomes), 18.8% of the participants originally assigned to pravastatin died, compared with 20.5% of those originally assigned to placebo. During the entire 15-year study period, the original pravastatin group had significant reductions in death from all causes (hazard ratio, 0.88), death from cardiovascular causes (HR, 0.81), and the composite of death from coronary heart disease and nonfatal MI (HR, 0.73), compared with the original placebo group. The greatest benefits with pravastatin occurred during the trial period — e.g., the reduction in death from cardiovascular causes was 34% during the trial and 14% in the post-trial period. Pravastatin treatment was not associated with an increase in cancer rates.


Comment: This study extends the findings of a classic statin trial: The benefits manifested during the trial were maintained — and perhaps expanded — through 10 years of follow-up. These results add to an already large literature supporting the value of statins for secondary prevention of coronary heart disease.