Adherence to Plant-Based Diets and Risk of CKD Progression and All-Cause Mortality: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study.

RATIONALE & OBJECTIVE: Studies have shown that generally healthy individuals who consume diets rich in plant foods have a lower risk of incident chronic kidney disease (CKD) and cardiovascular disease. This study investigated the prospective associations of plant-based diets with the risk of CKD progression and all-cause mortality in individuals with CKD. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 2,539 participants with CKD recruited between 2003-2008 into the Chronic Renal Insufficiency Cohort (CRIC) Study. EXPOSURE: Responses on the Diet History Questionnaire were used to calculate scores for the overall plant-based diet index, healthy plant-based diet index, and unhealthy plant-based diet index. OUTCOME: (1) CKD progression defined as≥50% estimated glomerular filtration rate decline from baseline or kidney replacement therapy (dialysis, transplant) and (2) all-cause mortality. ANALYTICAL APPROACH: Cox proportional hazards models to compute hazard ratios and 95% confidence intervals adjusting for lifestyle, socioeconomic, and clinical covariates. RESULTS: There were 977 CKD progression events and 836 deaths during a median follow-up period of 7 and 12 years, respectively. Participants with the highest versus lowest adherence to overall plant-based diets and healthy plant-based diets had 26% (HR, 0.74 [95% CI, 0.62-0.88], P trend<0.001) and 21% (HR, 0.79 [95% CI, 0.66-0.95], P trend=0.03) lower risks of all-cause mortality, respectively. Each 10-point higher score of unhealthy plant-based diets was modestly associated with a higher risk of CKD progression (HR, 1.14 [95% CI, 1.03-1.25) and all-cause mortality (HR, 1.11 [95% CI, 1.00-1.23). LIMITATIONS: Self-reported diet may be subject to measurement error. CONCLUSIONS: Adherence to an overall plant-based diet and a healthy plant-based diet is associated with a reduced risk of all-cause mortality among individuals with CKD. An unhealthy plant-based was associated with an elevated risk of CKD progression and all-cause mortality. PLAIN-LANGUAGE SUMMARY: Plant-based diets are healthful dietary patterns that have been linked to a lower risk of chronic diseases. However, the impact of plant-based diets on clinical outcomes in patients with chronic kidney disease (CKD) is not well established. In 2,539 individuals with CKD, we examined the associations of adherence to 3 different types of plant-based diets with the risks of CKD progression and all-cause mortality. We found that following an overall plant-based diet and a healthy plant-based diet was associated with a lower risk of all-cause mortality. By contrast, following an unhealthy plant-based diet was associated with a higher risk of CKD progression and all-cause mortality. These results suggest that the quality of plant-based diets may be important for CKD management.

Dietary Fiber Intake and Clinical Outcomes in Chronic Kidney Disease: A Report From the Chronic Renal Insufficiency Cohort Study.

OBJECTIVE: Dietary interventions are the mainstay of chronic diseases prevention in general population, but the evidence to support such therapeutic approaches in patients with chronic kidney disease (CKD) is less robust. The objective of this study is to examine the association between dietary fiber intake and adverse cardiovascular and kidney outcomes and all-cause mortality in participants with CKD enrolled in the Chronic Renal Insufficiency Cohort study. DESIGN AND METHODS: A total of 3791 Chronic Renal Insufficiency Cohort participants with self-reported dietary fiber intake were included in the analyses stratified by tertiles of dietary fiber at study baseline. Hazard ratios for occurrence of all-cause mortality, composite cardiovascular events and composite kidney events were calculated using Cox Proportional Hazards models adjusted for demographic, clinical, and laboratory characteristics, including levels of inflammatory markers, C-reactive protein and interleukin-6. RESULTS: Mean daily dietary fiber intake was 15.2 g/day. During a median (standard deviation) follow up of 14.6 (4.4) years, 1074 deaths from any cause occurred. In multivariable adjusted models, participants in the middle and low dietary fiber tertiles had a 19% (hazard ratio [95% CI]), 1.19 [1.02, 1.39]) and 11% (1.11 [0.95, 1.31]) greater risk of death respectively, compared to those in the highest fiber intake tertile. No statistically significant associations were observed between dietary fiber intake and adverse cardiovascular and kidney outcomes. Higher dietary fiber intake was not significantly associated with lower levels of C-reactive protein and interleukin-6. CONCLUSION: A lower intake of dietary fiber was not associated with all-cause mortality in participants with CKD after adjustments for kidney function and inflammatory biomarkers. There was no significant association between dietary fiber intake and adverse kidney and cardiovascular outcomes. Future randomized intervention trials are needed to identify whether a high dietary fiber intake translates into improved clinical outcomes in CKD.