Systematic review of the effect of diet and exercise lifestyle interventions in the secondary prevention of coronary heart disease

The effectiveness of lifestyle interventions within secondary prevention of coronary heart disease (CHD) remains unclear. This systematic review aimed to determine their effectiveness and included randomized controlled trials of lifestyle interventions, in primary care or community settings, with a minimum follow-up of three months, published since 1990. 21 trials with 10,799 patients were included; the interventions were multifactorial (10), educational (4), psychological (3), dietary (1), organisational (2), and exercise (1).The overall results for modifiable risk factors suggested improvements in dietary and exercise outcomes but no overall effect on smoking outcomes. In trials that examined mortality and morbidity, significant benefits were reported for total mortality (in 4 of 6 trials; overall risk ratio (RR) 0.75 (95%confidence intervals (CI) 0.65, 0.87)), cardiovascular mortality (3 of 8 trials; overall RR 0.63(95%CI 0.47, 0.84)), and nonfatal cardiac events(5 of 9 trials; overall RR 0.68(95%CI 0.55, 0.84)).The heterogeneity between trials and generally poor quality of trials make any concrete conclusions difficult. However, the beneficial effects observed in this review are encouraging and should stimulate further research.