Protein intake confers survival benefits for older adults with CKD

Older adults with chronic kidney disease (CKD) who consume high amounts of total, animal, and plant protein appear to have lower mortality, according to a study.

Researchers analysed data from three cohorts of community-dwelling adults who were at least 60 years of age (Study on Cardiovascular Health, Nutrition and Frailty in Older Adults in Spain 1 and 2, and the Swedish National Study on Aging and Care in Kungsholmen [Sweden]).

Cumulative protein intake was assessed using validated dietary histories and food frequency questionnaires. Chronic kidney disease was defined according to estimated glomerular filtration rates, urine albumin excretion, and diagnoses from medical records. Ten-year all-cause mortality, the primary outcome, was ascertained using national death registers.

The study sample comprised 8,543 participants and 14,399 observations. Of the participant observations, 4,789 had CKD stages 1 to 3 (mean age 78 years, 56.9 percent female). A total of 1,468 deaths were recorded during the follow-up.

Among participants with CKD, higher total protein intake (relative to 0.80 g/kg/d) was associated with lower mortality (1.00 g/kg/d: adjusted hazard ratio [HR], 0.88, 95 percent confidence interval [CI], 0.79–0.98; 1.20 g/kg/d: HR, 0.79, 95 percent CI, 0.66–0.95; 1.40 g/kg/d: HR, 0.73, 95 percent CI, 0.57–0.92).

The magnitude of reduction in mortality risk was comparable between plant and animal protein intakes (per 0.20-g/kg/d increment: HR, 0.80 and HR, 0.88, respectively) and between participants aged <75 years and those at least 75 years (per 0.20-g/kg/d increment in total protein intake: HR, 0.94 and HR, 0.91, respectively).

However, the hazard estimates were more favourable among participants without CKD than in those with CKD (per 0.20-g/kg/d increment: HR, 0.85 and HR, 0.92, respectively; p=0.02 for interaction), suggesting that the benefits of proteins might outweigh the downsides in older adults with mild or moderate CKD, according to the researchers.