Low-protein diet adherence and CKD progression during long-term follow-up

In early chronic kidney disease (CKD), a low-protein diet (LPD) may reduce glomerular hyperfiltration and delay progression, however, long-term studies in middle-income countries are limited. This study evaluates the impact of adherence to an LPD on CKD progression in Brazilian patients.

A total of 438 patients were studied from a single centre in Brazil between 2010 and 2024, comprising 306 patients who adhered to the LPD (<0.8 g/kg/day ± 10%) and 132 who did not adhere (>0.88 g/kg/day), based on calculations from 24-hour dietary recalls. The primary outcome was CKD progression, evaluated by the annual decrease in estimated glomerular filtration rate (eGFR). Progression was analysed both as a continuous variable (rate of eGFR decline over time) and by classification into normal decline (0-4.9 ml/min/year) or fast decline (>5 ml/min/year). A linear mixed model was used to evaluate the impact of adherence to an LPD on eGFR decline over time, adjusting for potential confounders.

The eGFR was comparable between groups, with adherent participants having a mean of 33.58 ± 13.71 ml/min/1.73 m2 and a mean age of 63.5 ± 13.8 years and the non-adherent group having a mean of 31.54 ± 13.18 ml/min/1.73 m2 and a mean age of 62.9 ± 15.3 years at baseline. Regarding protein intake and eGFR decline classification, no significant differences were observed between the groups. However, in the adjusted analysis, participants who adhered to the LPD had a significantly slower annual decline in eGFR compared with non-adherent individuals. The estimated mean annual change in eGFR was -0.29 ml/min/1.73 m2 for adherent participants and -1.40 ml/min/1.73 m2 for non-adherent participants. The absolute adjusted difference between groups was 1.10 ml/min/1.73 m2 (95% confidence interval 0.34-1.87; P = .0048).

The findings support the potential nephroprotective role of LPD adherence in prolonging kidney function, reinforcing the importance of dietary management in CKD treatment.