Dietary Plant Protein and Mortality Among Patients Receiving Maintenance Hemodialysis: A Cohort Study

Abstract

Rationale & objective: Although greater dietary intake of protein has been associated with beneficial health effects among patients receiving maintenance hemodialysis (MHD), the effects of plant protein intake are less certain. We studied the association of the proportion of protein intake derived from plant sources with the risk of mortality among patients receiving MHD and explored factors that may modify these associations.

Study design: Prospective observational cohort study.

Setting & participants: 1,119 Chinese hemodialysis patients aged over 18 years receiving MHD in 2014-2015.

Predictors: The proportion of plant protein intake to total protein intake.

Outcomes: All-cause mortality and cardiovascular disease (CVD) mortality.

Analytical approach: Segmented regression models were fit to examine the association of plant protein intake proportion with the risk of all-cause mortality and CVD mortality. Multivariable-adjusted Cox proportional and cause-specific hazards models were used to estimate the hazard ratios (HR) and 95% CI for these outcomes.

Results: The means of plant protein intake normalized to ideal body weight and plant protein intake proportion were 0.6±0.2 (SD) g/kg per day and 0.538±0.134, respectively. During a median follow-up period of 28.0 months, 249 deaths occurred, with 146 of these deaths resulting from CVD. Overall, there was a U-shaped association between plant protein intake proportion and the risk of all-cause mortality, with an inflection point at 45%. Among patients with a plant protein intake proportion<45%, there was a 17% lower rate of mortality with each 5% greater plant protein intake proportion (HR, 0.83 [95% CI, 0.73-0.96]). Among patients with plant protein intake proportion≥45%, there was a 9% greater rate of mortality with each 5% greater plant protein intake proportion. A similar U-shaped association was observed for CVD mortality, with an inflection point at 44%.

Limitations: Observational study, potential unmeasured confounding.

Conclusions: There was a U-shaped association between plant protein intake proportion and the risk of all-cause and cardiovascular mortality in MHD patients. If confirmed, these findings suggest a potential avenue to improve outcomes in this patient population.

Keywords: All-cause mortality; CVD mortality; cardiovascular disease (CVD); cohort study; diet; dietary protein; end-stage renal disease (ESRD); maintenance hemodialysis (MHD); modifiable risk factor; nutrition; plant protein intake proportion; soy.