Lack of Association between Dietary Fiber Intake and Kidney Failure among Patients with CKD: the CKD-JAC study.

OBJECTIVE

It remains unclear whether dietary fiber intake improves kidney outcome. The objective of our study was to examine the association between dietary fiber intake and the risk of kidney failure among patients with proteinuric chronic kidney disease (CKD).

METHODS

2,126 participants in the CKD-JAC (Chronic Kidney Disease-Japan Cohort) study were included in the current study. Dietary fiber intake was assessed using a self-administered Dietary History Questionnaire (DHQ). The outcome was the initiation of kidney replacement therapy (KRT). The inverse probability weighting (IPW)-Cox proportional hazards model was used to assess the association between dietary fiber intake and kidney outcome.

RESULTS

The mean (standard deviation) estimated glomerular filtration rate and urinary protein-to-creatinine (Cre) ratio were 28 (13) mL/min/1.73m and 1.4 (1.9) g/gCre, respectively. The median [interquartile range] dietary fiber intake was 10.4 [7.6-14.1] g/day. Serum potassium levels were comparable across quartiles of dietary fiber intake. During the median follow-up of 5.2 years, 823 initiated KRT (7.03 per 100 person-years). Although the highest quartile of total fiber intake was associated with a 37% [95% confidence interval: 30 to 48%] lower hazard of KRT initiation than the lowest quartile, their association became almost null after inverse probability weighting.

CONCLUSION

Higher dietary fiber intake was not associated with a lower risk of kidney failure among patients with proteinuric CKD.