Dietary Fiber Intake, Myocardial Injury, and Major Adverse Cardiovascular Events Among End-Stage Kidney Disease Patients: A Prospective Cohort Study

Abstract

Introduction: Dialysis patients are frequently advised to restrict fruit and vegetable intake due to their high potassium content. This study aimed to evaluate the association between dietary fiber intake and major adverse cardiovascular events (MACE) among dialysis patients.

Methods: A total of 219 prevalent dialysis patients were prospectively recruited from a major university teaching hospital and regional dialysis center in Hong Kong. Dietary fiber intake estimated using a 7-day locally validated food frequency questionnaire was examined in relation to a primary composite outcome of MACE over a follow-up period of 4 years.

Results: A total of 127 patients were complicated with 1 or more MACE. In the multivariable Cox regression analysis, every 1 g higher fiber intake, and every 1 g/d per 1000 kcal higher fiber intake density were associated with an 11% (95% confidence interval [CI]: 0.81-0.97) and a 13% lower risk of MACE (95% CI: 0.77-0.99), respectively, independent of clinical, demographic, biochemical, hemodynamic, adequacy parameters, dietary protein, energy intake, inflammatory, and cardiac markers. Patients in the lower tertile of fiber intake density showed an increased hazard for MACE (adjusted hazard ratio: 1.78; 95% CI: 1.13-2.80) than those in the upper tertile.

Conclusion: Higher fiber intake and higher fiber intake density may be associated with less inflammation, less myocardial hypertrophy, injury, and lower risk of MACE in dialysis patients. These data form an important basis for a randomized controlled trial to examine fiber supplementation on cardiovascular outcomes in the dialysis population.

Keywords: dialysis; fiber intake; major adverse cardiovascular events.

Graphical abstract

Figure 1

Cumulative major adverse cardiovascular event-free survival probabilities in relation to (a) dietary fiber intake stratified by tertiles and (b) fiber intake density stratified by tertiles. Dietary fiber intake >5.88 g/d as upper tertile (reference group), 3.71 g to 5.88 g/d as middle tertile, and <3.71 g as lower tertile. Fiber intake density defined as grams of daily fiber intake adjusted per 1000 kcal energy intake. Fiber intake density >4.10 g/d per 1000 kcal energy intake as upper tertile (reference group), 2.90 to 4.10, and <2.90 g/d per 1000 kcal energy intake as middle and lower tertiles, respectively.