Diet in secondary prevention: the effect of dietary patterns on cardiovascular risk factors in patients with cardiovascular disease: a systematic review and network meta-analysis

BACKGROUND

Improving dietary habits is a first-line recommendation for patients with cardiovascular disease (CVD). It is unclear which dietary pattern most effectively lowers cardiovascular risk factors and what the short- and long-term effects are. Therefore, this network meta-analysis compared the effects of popular dietary patterns on cardiovascular risk factors in patients with established CVD.

METHODS

A systematic search of PubMed, Embase, the Cochrane library, SCOPUS and Web of Science was conducted up to 1 April 2023. Randomized controlled trials (RCTs) comparing the effect of popular dietary patterns (Mediterranean, moderate carbohydrate, low glycemic index, low-fat and minimal dietary intervention) on cardiovascular risk factors (body weight, systolic blood pressure, lipids) in CVD populations were selected. A random-effects network meta-analysis was performed.

RESULTS

Seventeen RCTs comprising 6,331 participants were included. The moderate carbohydrate diet had the most beneficial effect on body weight (-4.6 kg, 95%CrI -25.1; 15.8) and systolic blood pressure (-7.0 mmHg 95%CrI -16.8; 2.7) compared to minimal intervention. None of the included dietary patterns had a favorable effect on low-density lipoprotein cholesterol. After 12 months, the effects were attenuated compared to those at < 6 months.

CONCLUSIONS

In this network meta-analysis of 17 randomized trials, potentially clinically relevant effects of dietary interventions on CV risk factors were observed, but there was considerable uncertainty due to study heterogeneity, low adherence, or actual diminished effects in the medically treated CVD population. It was not possible to select optimal dietary patterns for secondary CVD prevention. Given recent clinical trials demonstrating the potential of dietary patterns to significantly reduce cardiovascular event risk, it is likely that these effects are effectuated through alternative physiological pathways.

Effect of diet and lifestyle on the relationship between body mass index and waist circumference and cardiovascular mortality in myocardial infarction patients from the Alpha Omega Cohort

Introduction

The associations between measures of body adiposity body mass index (BMI) and waist circumference (WC) and cardiovascular disease (CVD) mortality have been frequently studied and usually follow a J-shaped curve or show a positive relationship. However, less is known about the influence of diet and physical activity on these associations.

Purpose

We aimed to gain insight in potential lifestyle-related effect modifiers of the association of BMI and WC with CVD mortality in myocardial infarction (MI) patients.

Methods

We included 4,837 Dutch patients from the Alpha Omega Cohort with a MI &lt;10 y prior enrolment. BMI and WC were assessed at baseline (2002–2006). Patients were followed through December 2018 for vital status and cause-specific mortality. Continuous associations of BMI and WC with CVD mortality were estimated using Cox proportional hazards models with restricted cubic splines. A BMI of 25 kg/m2 and a WC of 100 cm were used as the references. Age and sex adjusted associations were stratified for diet quality and physical activity level and interaction terms were calculated.

Results

Of the study population (69.0±5.6 y), 17% smoked, 21% had diabetes, 22% were female and &gt;85% used any type of cardiovascular medication. During a median follow-up of 12.4 years [8.5–13.8], 1,010 deaths occurred due to CVD. A J-shaped continuous association was observed between BMI and CVD mortality with inverse associations for a BMI between 25–30 kg/m2, compared to 25 kg/m2. The nadir (HR, 95% CI) was 27.4 kg/m2 (HR: 0.94, 95% CI: 0.88, 1.00) (A). For WC, a non-linear association was observed with CVD mortality with higher mortality risks for a WC above 100 cm (A). Results were similar in patients with low versus high diet quality and in patients with low versus high physical activity (B), interaction terms were not significant (all p&gt;0.55).

Conclusion

In MI patients, a BMI between 25–30 kg/m2 was associated with the lowest risk of CVD mortality. A WC above 100 cm was associated with a higher CVD mortality risk. The observed associations manifested independently of diet quality and physical activity level. Therefore, body adiposity seems to determine CVD mortality risk independently of underlying lifestyle factors.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Regio Deal Foodvalley