Effects of a low-protein nutritional formula with dietary counseling in older adults with chronic kidney disease stages 3-5: a randomized controlled trial

Abstract

Background: Although combining a low-protein diet (LPD) with oral nutritional supplements increases treatment adherence and nutritional status in patients with chronic kidney disease (CKD), the effect of this combination approach in older adults remains unclear. This study examined the impact of a 6% low-protein formula (6% LPF) with diet counseling in older adults with stage 3-5 CKD.

Methods: In this three-month randomized controlled study, 66 patients (eGFR < 60 mL/min/1.73 m², non-dialysis, over 65 years of age) were randomly assigned to an intervention group (LPD plus a 6% LPF) or control group (LPD alone). The 6% LPF comprised 400 kcal, 6 g of protein, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and various micronutrients. All data were collected at baseline and after three months, including physical performance based on hand grip strength (HGS) and gait speed, nutritional status using Mini Nutritional Assessment-Short Form (MNA-SF) scores, body composition through bioelectrical impedance analysis, and dietary intake from 24-h dietary records.

Results: This study incorporated 47 participants (median age, 73; median eGFR, 36 ml/min/1.73 m²; intervention group: 24; control group: 23). The intervention group exhibited significant differences in HGS and gait speed, and micronutrient analysis revealed significantly higher monounsaturated fatty acids (MUFA), EPA, DHA, calcium, iron, zinc, copper, thiamine, riboflavin, niacin, B6, B12, and folic acid intake than the control group. MNA-SF scores, macronutrient intake, and body composition did not differ significantly between the two groups.

Conclusions: Compared to LPD counseling alone, an LPD prescription with 6% LPF in older adults with CKD stages 3-5 helped relieve physical deterioration and increased micronutrient intake after three months.

Trial registration: ClinicalTrials.gov NCT05318014 (retrospectively registered on 08/04/2022).

Keywords: Aging; Chronic kidney disease; Gait speed; Hand grip strength; Low-protein diet; Nutritional status; Oral nutritional supplements; Physical performance.

Fig. 1

CONSORT flow diagram of participant recruitment

Fig. 2

The box plot displays the physical performance parameters from a three-month treatment follow-up. A Hand grip strength (kg). B Gait speed (m/s). Data are expressed as the median (interquartile range). Comparisons within groups from baseline to three months were performed using the Wilcoxon signed-rank test (†P < 0.05). Value change differences between intervention and control groups as determined by the Mann–Whitney U test (*P < 0.05, ** P < 0.01)