This study shows that even in intensely pharmacologically-treated CVD patients who received cardioprotective drug treatment, a comprehensive lifestyle intervention had a beneficial effect on some cardiovascular risk factors. The intervention decreased BMI and waist circumference, and increased exercise capacity and levels of moderate/heavy physical activity. There was no added significant effect on any other outcome measure.
The results achieved with this multidisciplinary structured lifestyle intervention programme of improvement in physical activity, BMI and exercise capacity are in line with other intensive lifestyle programmes for patients with a history of CVD [36
]. For instance the EUROACTION preventive cardiology programme, that was quite similar to the intervention in this study, also led to some weight loss and for high risk patients in a reduction of central obesity. No significant effects were found on lipid levels. The programme also improved blood pressure control without the use of additional antihypertensive drugs [9
]. However in our study setting, cardiovascular risk management for blood pressure and lipid levels by prescription of medical prophylactic treatment for CVD in usual care was close to optimal (as reflected in baseline levels); therefore, the additional benefit of the lifestyle intervention over usual care for blood pressure and lipid levels was small and not significant. Even though the smoking cessation strategy used in the present study was evidence based, few patients ceased smoking; this might be due to the small numbers involved. In a Cochrane review the overall effect of psychosocial smoking cessation interventions in CHD patients was expressed by a number needed to treat of 9.7 [39
]. This means that about 10 patients had to be treated for one person to have abstained from smoking after 1 year. Another explanation could be the relatively high percentage of heavy smokers in our study population. Similarly, other studies found a higher prevalence of heavy smokers in those who continue to smoke or who relapse after a cardiac event [40
]. It remains unclear which method is most effective to help these patients stop smoking [40
There was no effect on estimated 10-year risk of cardiovascular morbidity and total mortality. One reason could be the latency of effects, i.e. benefits might not be detected in the early stages but may emerge over time. The present study may have been too short to show an impact on morbidity and mortality. Another reason could be that the individual risk assessment was performed using the Copenhagen Risk Score [32
]; although this score is suitable for many of the parameters in the present study, it does not allow input of exercise capacity as an independent risk factor. The positive effect of exercise on cardiovascular morbidity and mortality has been well documented [43
]. Myers et al. reported that exercise capacity was a stronger predictor of mortality than other established risk factors in men with a history of CVD [44
]. Manson et al. [45
] reported that both walking and vigorous exercise are associated with substantial reductions in the incidence of cardiovascular events irrespective of age and body mass index. Thus, in the present study, the calculated risk score probably underestimated the protective effect of the lifestyle intervention.
The strength of the study is its randomised design which reduces the chance of confounding.
A limitation is that all patients were receiving cardiovascular medication at baseline, and medication use for patients that successively altered their lifestyle was not lowered. Therefore, we could not prove the additional benefit of the intervention over usual care for blood pressure and lipid levels. However, nowadays it is not feasible to recruit patients with established CVD that are not on cardiovascular medication and (of course) it is unethical to stop providing such medication to patients randomised to the intervention group.
A potential limitation of the external validity of this study is the non-response of patients eligible to participate. Participants were higher educated, slightly younger, and more often still at work compared with non-responders. Also, patients participating in a trial may be more amenable to behavioural change than those declining participation. Therefore, our conclusions may not apply to patients with a lower education level or those less motivated to change their lifestyle.
In this study we had problems with the recruitment of patients. The main reason was that eligible patients refused to participate. Low participation rates for secondary prevention programmes have been reported repeatedly [46
]. Another reason was the lack of financial resources. During the recruitment period of the study there was a change in policy of the health insurance companies. Consequently, the intervention was no longer reimbursed for patients and we had to stop recruitment. A post-hoc power calculation showed that we were still able to assess the effectiveness of the programme on clinical outcomes.
The present findings may have implications for policy on preventive cardiology for patients with established CVD and for future research.
First, the results show that the benefits of lifestyle intervention are sustained in the present era of widespread cardiovascular therapy. Moreover, there is a growing population of overweight, obese and physically inactive CVD patients [10
]. These trends cannot be effectively targeted with medication alone and this trial confirms the benefits of lifestyle modification on these risk factors. Our results are an encouraging sign that preventive cardiology can be further improved. An economic evaluation is needed to determine the cost-effectiveness of the intervention.
Current evidence shows the benefits of a wide variety of secondary prevention programmes including less intensive and shorter versions [4
]. In the Netherlands distances to clinics are relatively short. For many countries and rural areas less intensive interventions may be a good alternative, because they are easily accessible and less costly. However, this may not extend to a clinically more complicated older, fragile population that tends to be more complex in terms of co-morbidities and treatment regimen. They may need close supervision [3
]. Future research should investigate the effectiveness and cost-effectiveness of less intensive interventions compared with more intensive interventions.
Second, we recommend that future strategies for cardiovascular risk reduction should begin with lifestyle modification and introduce or lower prophylactic cardiovascular medication later on if required. Lifestyle modifications avoid the adverse effects associated with medication and are less costly than long-term medication.
Third, a large trial is needed to compare usual care with an intervention aimed at lifestyle modifications together with the active lowering of medication.