Synbiotics Easing Renal Failure by Improving Gut Microbiology II (SYNERGY II): A Feasibility Randomized Controlled Trial

Study answer

What this study found

Feasibility and acceptability were high: recruitment from eligible patients and 12-month retention were favorable; adherence was high; GI symptoms and stool consistency did not differ between groups. No differences in echocardiographic measures or IS/PCS concentrations. However, synbiotic supplementation reduced eGFR by 3.14 mL/min/1.73 m^2 and increased serum creatinine by 20.8 μmol/L over 12 months (p<0.01); two participants had >40% eGFR decline. No significant changes in stool diversity; modest shifts in gut microbiota and function were observed. Uremic toxins IS and PCS did not change.…

Study & population

Double-blind, placebo-controlled randomized trial in adults with CKD stage 3-4; eGFR 15-60 mL/min/1.73 m^2; age ≥18; two tertiary kidney care outpatient departments; 68 randomized; baseline: 66% men; median age 70 (IQR 58-75); median eGFR 34 (IQR 27-41).

Intervention

Prebiotic Hi-Maize 260, 20 g/day plus probiotic blend 4.5 × 10^11 CFU/day across nine strains (Lactobacillus acidophilus, L.

Key limitation

Small sample size with limited power for secondary outcomes; use of surrogate outcomes; limited generalizability to CKD patients outside eGFR 15–60 mL/min/1.73 m^2; not measuring 24-h urine albumin/proteinuria; single 12-month duration across two sites; metabolomic data not included but suggested for future work.

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Original abstract