The Association Between Total Protein Intake and All-Cause Mortality in Middle Aged and Older Korean Adults With Chronic Kidney Disease

Abstract

Background and AimsOver the past decades, the optimum protein intake for patients with chronic kidney disease (CKD) has been an important, controversial issue. Dietary protein restriction has been commonly recommended for patients with CKD for preserving kidney function. However, evidence of the associations between long-term protein intake and mortality is not consistent in patients with CKD. Therefore, we aimed to examine the associations between total protein intake and all-cause mortality in Korean adults with CKD.MethodsFrom three sub-cohorts of the Korean Genome and Epidemiology Study (KoGES) starting from 2001, total 3,892 participants with eGFR < 60 mL/min/1.73 m2 (CKD stage 3–5) were included in this study. Dietary data were collected using food-frequency questionnaires at baseline. Deaths were followed from 2001 to 2019. Cox proportional hazards regression model was used to evaluate the association between protein intake and all-cause mortality.ResultsDuring a median follow-up (min-max) of 11.1 years (0.3–15.1), 602 deaths due to all causes of mortality were documented. After adjustment for covariates, higher total protein intake was not associated with all-cause mortality [highest vs. lowest quintile of total protein intake (g/kg/day) and proportion (%) (Q5 vs. Q1), HR = 1.14 (0.75–1.72), and HR = 0.87 (0.67–1.13)] in CKD stage 3–5 patients.ConclusionDietary protein intake was not associated with mortality from all causes in patients with CKD. Further research is needed to establish optimal protein intake levels and examine the impact of the dietary source of protein on various health outcomes and mortality in CKD.

Protein Intake and Mortality in Older Adults With Chronic Kidney Disease

“…Results of this multicohort study are in line with those of observational studies [10][11][12] that have found neutral or inverse associations between protein intake and mortality among older persons with CKD stages 3 to 5 not receiving dialysis. First, in 3892 middle aged and older Korean adults, higher total protein intake showed a null association with 11-year all-cause mortality.…”

“…First, in 3892 middle aged and older Korean adults, higher total protein intake showed a null association with 11-year all-cause mortality. 10 Second, among 356 French patients with CKD over 60 years, higher total protein intake was not associated with increased mortality after 3 years. 12 Third, in 259 Japanese adults with CKD and older than 65 years, higher total protein intake was associated with lower risk of all-cause death over 4 years, although participants had been advised to limit protein intake depending on their CKD stage.…”

“…[4][5][6] The latest guidelines leave the door open for higher protein intake targets in those with underlying conditions, such as frailty and sarcopenia, but more data are needed to make specific recommendations. 5 Observational studies on mortality in older persons with CKD are often small to moderate in size, are conducted in a single setting, and use point-in-time estimates of protein intake, [10][11][12] while randomized clinical trials commonly include participants with CKD of all ages and lack power to analyze protein intake modification in those who are older. 13,14 The role of protein sources in older adults with CKD is also of interest.…”

Relationship between different forms of dietary choline and ovarian cancer survival: findings from the ovarian cancer follow-up study, a prospective cohort study

“…68 Fourth, all OC patients used in our study were Chinese; it might be difficult for our findings to be generalized to populations with different racial and socio-economic distributions because dietary habits, food selections, and cooking methods between various populations may differ. 69 Fifth, our study explored the relationship between dietary choline before diagnosis and OC prognosis, without exploring the effect of dietary choline after diagnosis. Future studies should consider this issue.…”