The benefits of treating hyperlipidemia to prevent coronary heart disease. Estimating changes in life expectancy and morbidity.

OBJECTIVE

To evaluate the lifetime benefits of reducing total serum cholesterol levels to prevent coronary heart disease (CHD).

DESIGN

We developed a CHD primary prevention computer model to estimate the benefits associated with lifelong risk factor modification. We validated the model by comparing the computer estimates with the observed results of three primary CHD prevention trials.

PATIENTS

Men and women age 35 to 65 years who are free of CHD, with total serum cholesterol levels ranging from 5.2 to 7.8 mmol/L (200 to 300 mg/dL), with or without additional CHD risk factors.

INTERVENTIONS

Serum cholesterol reduction through dietary modification or diet and medications.

MAIN OUTCOME MEASURES

Changes in life expectancy and the delay of symptomatic CHD.

RESULTS

The computer forecasts for CHD end points closely matched the observed results of the Lipid Research Clinics Trial, the Helsinki Heart Study, and MRFIT. We then applied the computer model to low-risk and high-risk men and women with total serum cholesterol levels between 5.2 and 7.8 mmol/L (200 and 300 mg/dL) and estimated that, after reducing serum cholesterol levels 5% to 33%, the average life expectancy would increase by 0.03 to 3.16 years. We also forecast that the average onset of symptomatic CHD would be delayed among these patient groups by 0.06 to 4.98 years.

CONCLUSION

We conclude that this computer model accurately estimates the results of clinical trials and can be used to forecast the changes in life expectancy and morbidity (the development of CHD) associated with specific CHD risk reduction interventions. The wide variation surrounding these estimates underscores the need to better define which groups of individuals will gain the most from cholesterol reduction.