The Helsinki Heart Study: coronary heart disease incidence during an extended follow-up.

OBJECTIVES

To confirm that coronary heart disease (CHD) can be prevented by gemfibrozil treatment and to estimate the long-term effect of the treatment.

DESIGN

All participants of the Helsinki Heart Study, a controlled 5-year CHD primary prevention trial with gemfibrozil and placebo, were offered gemfibrozil treatment and biannual follow-up for 3.5 more years.

SETTING

By the end of the multi-clinic double-blind trial, a 34% difference in definite cardiac events (56 vs. 84; P < 0.2) had developed between the gemfibrozil and placebo groups.

SUBJECTS

There were 2046 dyslipidaemic men in the gemfibrozil group at randomization, 1961 started the extended follow-up; the comparison group comprised 2035 men, and 5 years later 1928 men.

INTERVENTIONS

Gemfibrozil was selected by 66.3% of gemfibrozil and 68.5% of placebo men without previous CHD end-points.

MAIN OUTCOME MEASURES

Definite fatal and non-fatal CHD events are reported, possible CHD events were recorded but reported selectively.

RESULTS

During the post-trial period the numbers of definite CHD events in both groups (54 vs. 47; NS) were smaller than expected without treatment, namely a reduction of around 40% for the original treatment groups. The mean incidence rates were in fact similar to that in the placebo group 5 years earlier. The post-trial CHD incidence was lowest amongst the placebo group men who later selected gemfibrozil. Cardiovascular mortality over the entire study period was similar but all-cause mortality was slightly higher amongst men of the original gemfibrozil group compared to the placebo group men (P = 0.19).

CONCLUSIONS

Thus prolonged gemfibrozil treatment postpones cardiac events. This protective effect presumably involves both attenuation of atherosclerosis and mechanisms related to acute cardiac events.