Adherence to Healthy Dietary Patterns and Risk of CKD Progression and All-Cause Mortality: Findings From the CRIC (Chronic Renal Insufficiency Cohort) Study

Abstract

Rationale & objective: Current dietary guidelines recommend that patients with chronic kidney disease (CKD) restrict individual nutrients, such as sodium, potassium, phosphorus, and protein. This approach can be difficult for patients to implement and ignores important nutrient interactions. Dietary patterns are an alternative method to intervene on diet. Our objective was to define the associations of 4 healthy dietary patterns with risk for CKD progression and all-cause mortality among people with CKD.

Study design: Prospective cohort study.

Setting & participants: 2,403 participants aged 21 to 74 years with estimated glomerular filtration rates of 20 to 70mL/min/1.73m² and dietary data in the Chronic Renal Insufficiency Cohort (CRIC) Study.

Exposures: Healthy Eating Index-2015, Alternative Healthy Eating Index-2010, alternate Mediterranean diet (aMed), and Dietary Approaches to Stop Hypertension (DASH) diet scores were calculated from food frequency questionnaires.

Outcomes: (1) CKD progression defined as≥50% estimated glomerular filtration rate decline, kidney transplantation, or dialysis and (2) all-cause mortality.

Analytical approach: Cox proportional hazards regression models adjusted for demographic, lifestyle, and clinical covariates to estimate hazard ratios (HRs) and 95% CIs.

Results: There were 855 cases of CKD progression and 773 deaths during a maximum of 14 years. Compared with participants with the lowest adherence, the most highly adherent tertile of Alternative Healthy Eating Index-2010, aMed, and DASH had lower adjusted risk for CKD progression, with the strongest results for aMed (HR, 0.75; 95% CI, 0.62-0.90). Compared with participants with the lowest adherence, the highest adherence tertiles for all scores had lower adjusted risk for all-cause mortality for each index (24%-31% lower risk).

Limitations: Self-reported dietary intake.

Conclusions: Greater adherence to several healthy dietary patterns is associated with lower risk for CKD progression and all-cause mortality among people with CKD. Guidance to adopt healthy dietary patterns can be considered as a strategy for managing CKD.

Keywords: CKD progression; Dietary patterns; chronic kidney disease (CKD); dietary intake; dietary score; food frequency questionnaire (FFQ); healthy eating; modifiable risk factor; mortality; nutrition; renal.

Figure 1.. Risk of chronic kidney disease progression by component of aMed score (comparing tertile 3 to tertile 1)

Risk of chronic kidney disease progression by component of aMed score (comparing tertile 3 to tertile 1)^a. ^a Cox proportional hazards models to estimate hazard ratios (HR) and 95% confidence intervals (CI) on a logarithmic scale. Hazard ratios can be interpreted as the likelihood of chronic kidney disease progression comparing participants in tertile 3 to participants in tertile 1 for the given component of aMed score. Models were adjusted for total energy intake, clinical site, age, sex, race, education, income level, estimated glomerular filtration rate, urinary protein, smoking status, physical activity, body mass index, diabetes mellitus, hypertension, cardiovascular disease, high-density lipoprotein cholesterol, angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker use, and all other components of the aMed score. aMed, alternate Mediterranean diet; MUFA, monounsaturated fatty acids; SFA, saturated fatty acids.