Long-Term Outcomes of the DASH Intervention in Nonobstructive Coronary Artery Disease: Follow-Up of the DISCO-CT Study

Introduction

Coronary artery disease (CAD) remains a leading cause of morbidity and mortality worldwide. Nonobstructive CAD, characterized by the presence of atherosclerotic plaques without significant luminal narrowing, still poses considerable cardiovascular risk. Lifestyle modification, particularly dietary intervention, is a cornerstone in managing CAD to prevent disease progression and adverse outcomes.

The Dietary Approaches to Stop Hypertension (DASH) diet is recognized for its cardiovascular benefits, emphasizing fruits, vegetables, whole grains, lean proteins, and low sodium intake. The randomised Dietary Intervention to Stop Coronary Atherosclerosis using Computed Tomography (DISCO-CT) trial investigated the effects of a 12-month DASH intervention led by dietitians in patients with nonobstructive CAD. Initial results from this trial demonstrated improvements in cardiovascular and metabolic risk factors, along with reductions in platelet chemokine levels, particularly CXCL4, which is implicated in atherogenesis. However, the durability of these benefits remained uncertain.

Study Objectives

This follow-up study aimed to evaluate whether the metabolic improvements, inflammatory modulation, and clinical benefits achieved during the structured DISCO-CT intervention persist six years after the program’s completion. Assessing long-term adherence and clinical outcomes is crucial for understanding the sustained impact of lifestyle interventions in CAD management.

Methods

Ninety-seven adult participants diagnosed with nonobstructive CAD via coronary computed tomography angiography (CCTA) were randomized into two groups: the control group receiving optimal medical therapy alone (n=41), and the DASH group receiving the same therapy plus intensive, dietitian-led DASH dietary counseling (n=43).

After an average follow-up period of approximately 301 weeks (about six years), 84 participants who consented underwent comprehensive reassessment. This included body composition measurements, evaluation of meal frequency, and biochemical analyses measuring lipids, high-sensitivity C-reactive protein (hs-CRP), chemokines CXCL4 and RANTES, and homocysteine levels. Major adverse cardiovascular events (MACE), such as myocardial infarction, stroke, and cardiovascular death, were tracked and compared.

Results

During the initial 12-month intervention, the DASH group experienced significantly greater weight loss and fat reduction compared to controls. Specifically, the DASH group lost an average of 3.6 ± 4.2 kg in body weight and reduced total body fat by 4.2 ± 4.8 kg. In contrast, the control group lost 1.1 ± 2.9 kg body weight and reduced fat by only 0.3 ± 4.1 kg (p < 0.01 for both).

Six years after intervention completion, most of the lost weight and fat were regained in both groups. Notably, visceral fat area – the fat surrounding internal organs and a strong predictor of cardiovascular risk – increased sharply in both groups (p < 0.0001).

Regarding inflammatory markers, CXCL4 levels decreased significantly by 4.3 ± 3.0 ng/mL during the intervention in the DASH group and remained lower than baseline even after six years. Conversely, in the control group, CXCL4 initially rose post-baseline before declining below baseline but remained higher than in the DASH group at follow-up (p < 0.001 between groups). LDL cholesterol and hs-CRP levels in both groups returned toward baseline values at six years but stayed consistently lower in the DASH group.

Clinically, the DASH group reported only one MACE event during follow-up, while the control group experienced four events, including one fatal myocardial infarction (p=0.575, not statistically significant due to the small event rate).

Adherence to the DASH dietary pattern increased markedly during active counseling by 26 points but declined only minimally by four points six years later, remaining significantly higher than in the control group.

Discussion

This long-term follow-up suggests that a one-year structured DASH diet intervention, supported by healthcare professionals, yields durable benefits in certain inflammatory markers linked to atherogenesis, especially CXCL4, a chemokine involved in platelet activation and vascular inflammation.

Although anthropometric benefits, such as weight and fat reduction, diminished over time, the sustained suppression of proatherogenic chemokines may partly explain the trend toward fewer major cardiovascular events in the DASH group.

The increase in visceral fat despite initial intervention success highlights challenges in maintaining lifestyle changes over extended periods without ongoing support. Visceral adiposity correlates strongly with metabolic syndrome and cardiovascular risk, underscoring the need for continuous reinforcement of healthy habits.

Notably, the cardiovascular event rate was low overall, which limits definitive conclusions regarding MACE risk reduction. Nevertheless, the trend favors lifestyle intervention complemented by medical therapy.

Clinical Implications

Sustained behavioral changes are essential to maintain the initial metabolic and inflammatory benefits of dietary interventions in CAD management. Regular follow-up, possibly with intermittent reinforcement from dietitians and clinicians, may be necessary to preserve adherence and prevent relapse into unhealthy dietary patterns.

The findings support integrating structured dietary programs like DASH into standard care for patients with nonobstructive CAD, emphasizing multidisciplinary collaboration.

Conclusion

A 12-month dietitian-led DASH intervention in individuals with nonobstructive CAD resulted in long-term suppression of the proatherogenic chemokine CXCL4 and a lower incidence of major adverse cardiovascular events over six years despite declines in adherence and loss of the majority of anthropometric improvements. These findings highlight the importance of ongoing behavioral reinforcement to sustain lifestyle intervention benefits and optimize cardiovascular outcomes.

Reference

Makarewicz-Wujec M, Henzel J, Kępka C, Kruk M, Jakubczak B, Wróbel A, Dąbrowski R, Dzielińska Z, Demkow M, Czepielewska E, Filipek A. Long-Term Outcomes of the Dietary Approaches to Stop Hypertension (DASH) Intervention in Nonobstructive Coronary Artery Disease: Follow-Up of the DISCO-CT Study. Nutrients. 2025 Aug 6;17(15):2565. doi:10.3390/nu17152565. PMID: 40806149; PMCID: PMC12348568.