High-protein diet with renal hyperfiltration is associated with rapid decline rate of renal function: a community-based prospective cohort study.

BACKGROUND: The effect of a high-protein diet with renal hyperfiltration (RHF) on decline of kidney function has rarely been explored. We investigated the association between a high-protein diet, RHF and declining kidney function.

METHODS: A total of 9226 subjects from the Korean Genome and Epidemiology Study, a community-based prospective study (2001-14), were enrolled and classified into quartiles according to daily amount of protein intake based on food frequency questionnaires. RHF was defined as estimated glomerular filtration rate (eGFR) with residuals of >95th percentile after adjustment for age, sex, history of hypertension or diabetes, height and weight. Rapid decline of renal function was defined as decline rate of eGFR >3 mL/min/1.73 m2/year.

RESULTS: The relative risk of RHF was 3.48-fold higher in the highest than in the lowest protein intake quartile after adjustment for confounding factors [95% confidence interval (CI) 1.39-8.71]. The mean eGFR decline rate was faster as quartiles of protein intake increased. Furthermore, the highest quartile was associated with 1.32-fold increased risk of rapid eGFR decline (95% CI 1.02-1.73). When subjects were divided into two groups with or without RHF, the highest quartile was associated with a rapid decline in renal function only in RHF subjects (odds ratio 3.35; 95% CI 1.07-10.51). The sensitivity analysis using the Korean National Health and Nutrition Examination Survey (2008-15) data with 40 113 subjects showed that higher quartile was associated with increased risk for RHF.

CONCLUSIONS: A high-protein diet increases the risk of RHF and a rapid renal function decline in the general population. These findings suggest that a high-protein diet has a deleterious effect on renal function in the general population.