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.

Prevalence and determinants of self-reported low-fat-, low-salt-, and vegetarian diets in patients with cardiovascular disease between 1996 and 2019.

BACKGROUND AND AIMS: Guidelines no longer recommend low-fat diets and currently recommend more plant-based diets to reduce atherosclerotic cardiovascular disease (ASCVD) risk. Furthermore, these guidelines have consistently recommended salt-reduced diets. This article describes current self-reported use and time-trends in the self-reported use of low-fat, low-salt and vegetarian diets in ASCVD patients and examines patient characteristics associated with each diet. METHODS AND RESULTS: 9005 patients with ASCVD included between 1996 and 2019 in the UCC-SMART cohort were studied. The prevalence of self-reported diets was assessed and multi-variable logistic regression was used to identify the determinants of each diet. Between 1996-1997 and 2018-2019, low-fat diets declined from 22.4 % to 3.8 %, and low-salt diets from 14.7 % to 4.6 %. The prevalence of vegetarian diets increased from 1.1 % in 1996-1997 to 2.3 % in 2018-2019. Patients with cerebrovascular disease (CeVD) and peripheral artery disease or an abdominal aortic aneurysm (PAD/AAA) were less likely to report a low-salt diet than coronary artery disease (CAD) patients (OR 0.62 [95%CI 0.49-0.77] and 0.55 [95%CI 0.41-0.72]). CONCLUSION: In the period 1996 to 2019 amongst patients with ASCVD, the prevalence of self-reported low-fat diets was low and decreased in line with changes in recommendations in major guidelines. The prevalence of self-reported vegetarian diets was low but increased in line with societal and guideline changes. The prevalence of self-reported low-salt diets was low, especially in CeVD and PAD/AAA patients compared to CAD patients, and decreased over time. Renewed action is needed to promote low-salt diets in ASCVD patients.

Effect of dietary patterns on cardiovascular risk factors in people with type 2 diabetes. A systematic review and network meta-analysis.

AIMS: To identify the most effective dietary pattern for improving cardiovascular risk factors in people with type 2 diabetes. METHODS: PubMed, Embase, the Cochrane library, SCOPUS and Web of Science were systematically searched for randomized controlled trials comparing the effects of dietary patterns on body weight, blood pressure, HbA1c and lipids after 6 and 12 months. Treatment effects were synthesized using Bayesian network meta-analysis. Six-month changes in HbA1c, SBP and LDL-C were used to estimate relative risk reductions (RRR) for cardiovascular events. RESULTS: Seventy-three RCTs on eight different dietary patterns were included. All reduced body weight and HbA1c after 6 months, with the largest effects from the low carbohydrate (body weight -4.8 kg, 95 %credibility interval (95 %CrI) -6.5;-3.2 kg) and Mediterranean diet (HbA1c -1.0 %, 95 %CrI -15;-0.4 % vs usual diet). There were no significant 6-month blood pressure or lipid effects. Dietary patterns had non-statistically significant 12-months effects. The Mediterranean diet resulted in the largest expected RRR for cardiovascular events: -16 % (95 %CI -31;3.0) vs usual diet. CONCLUSIONS: In patients with type 2 diabetes, all dietary patterns outperformed usual diet in improving body weight and HbA1c after 6 months and clinically relevant cardiovascular risk reduction could be achieved. There was insufficient evidence to select one optimal dietary pattern.