Dietary interventions for adults with chronic kidney disease.

Systematic review of 17 studies involving 1639 adults with chronic kidney disease at any stage, including people on dialysis and kidney transplant recipients. Trials compared different dietary interventions with usual care or alternative diets, and the evidence was synthesized across clinical and biochemical outcomes.

This review evaluated a range of oral dietary interventions rather than a single supplement regimen. Active interventions included individualized dietary counselling, Mediterranean-type diets, low-protein or low-salt diets, fruit and vegetable prescriptions, and other individualized nutrition programs, with durations ranging from 4 weeks to 24 months depending on the trial.

Dietary interventions showed uncertain effects on hard kidney and survival outcomes, but some trials suggested improvements in quality of life, blood pressure, eGFR, serum albumin, and LDL cholesterol. In pooled analyses, all-cause mortality was inconclusive (RR 1.59, 95% CI 0.60 to 4.21), as was progression to end-stage kidney disease (RR 0.53, 95% CI 0.26 to 1.07). Health-related quality of life improved in two studies (MD 11.46, 95% CI 7.73 to 15.18), and pooled effects favored lower systolic blood pressure (MD -9.26 mm Hg) and higher serum albumin (MD 0.16 g/dL). Overall, the authors concluded that evidence remains very low quality and too heterogeneous to guide clinical practice confidently.

Evidence quality was very low, with high or unclear risk of bias across studies. Interventions were highly heterogeneous in content, intensity, duration, and comparator, and many clinically important outcomes such as mortality and progression to kidney failure were rarely measured or reported. Several pooled analyses were small and imprecise, with substantial heterogeneity for some outcomes such as eGFR and systolic blood pressure.