Protein intake and its relationship with frailty in chronic kidney disease

Patients with chronic kidney disease (CKD) are susceptible to frailty because of a range of nutrition-related factors. While protein restriction is commonly advised to preserve kidney function in patients with CKD, insufficient protein intake could potentially exacerbate frailty risk. This study aimed to elucidate the relationship between frailty and protein intake in patients with CKD.

This cross-sectional study enrolled patients with CKD stage 3-5. Frailty and prefrailty were assessed using the Japanese version of the Cardiovascular Health Study (J-CHS) criteria. To estimate dietary protein intake, Maroni's formula based on 24-h urine collection was used. The potential association between frailty/pre-frailty and protein intake was investigated using a logistic regression analysis.

Ninety-seven individuals with CKD were included in the study, with a median age of 73.0 years (interquartile range: 67.0, 82.0). Among them, 34 were women (35.1%), and the estimated glomerular filtration rate (eGFR) was 36.3 mL/min/1.73 m² (interquartile range: 26.9, 44.1). Frailty and pre-frailty were identified in 13.4% and 55.7% of participants, respectively. Comparing the groups, protein intake in the frailty/pre-frailty group (0.83 g/kgBW/day [0.72, 0.93]) was lower than that in the robust group (0.89 g/kgBW/day [0.84, 1.19], p = 0.002). Upon logistic regression analysis, protein intake exhibited an independent association with frailty/pre-frailty (odds ratio: 0.72, 95% confidence interval: 0.59-0.89, p = 0.003).

Reduced protein intake in patients with CKD is associated with frailty and pre-frailty. It is advisable to ensure that patients with CKD who are at risk of frailty consume an adequate amount of protein.