Introduction
Chronic kidney disease (CKD) prevalence rises with age and affects approximately 44% of people aged 75+. Stage 1 and 2 (GFR>60) in the elderly is not considered a disease state unless there is haematuria or albuminuria or structural change. [1]
Intervention
Dietary interventions, (salt and or protein restriction).
Indication
Adults with chronic kidney disease stages 3a -5 i.e. sustained GFR <60 mL/min/1.73m2
Precautions / Adverse effects
In older patients, a low-protein diet may increase their risk of malnutrition and sarcopenia.
A low sodium diet can increase risk of symptomatic hypotension (estimated 5% risk, Moderate GRADE evidence)
Availability
Discuss dietary salt and protein with patients with CKD. Where possible, referral to an Accredited Practising Dietitian is recommended.
Description
The following summarises the evidence on salt and protein:
- Reducing salt by mean equivalent to 4.2 g or 1690 mg sodium/day has been shown to:
- Reduce blood pressure in people with CKD (mean is by about 7mmHg systolic, High GRADE Evidence)
- Reduce Albuminuria in people with pre dialysis stage CKD (mean reduction 36%, High GRADE evidence [3])
- Reduce extracellular fluid volume (Low GRADE Evidence)
- A salt intake of <5g/day (<2000 mg sodium) is recommended by Kidney Health Australia. Salt intake is often double this amount in patients with CKD [2].
- A low-protein diet is associated with lower rates of progression to end-stage renal disease.[2] The recommended daily intake of protein for people with a GFR 30–59 mL/min/1.73m2 is 0.75–1 g/kg body weight.[4]
Tips and Challenges
Tips on reducing salt intake:
- Avoid adding salt during cooking or at the table
- Choose salt-reduced packaged food products
- Avoid salt substitutes with high levels of potassium if the patient has a history of hyperkalemia
- Antihypertensive medications may need to be reduced (about 5% risk Very Low GRADE evidence)
Tips for protein intake:
- At 0.75–1 g/kg body weight of protein per day, the recommended protein amount for a 75 kg person would be about 75 g. Apps such as My Fitness Pal or calorieking.com.au can help with tracking protein intake.
- Patients with CKD may benefit from dietary advice for other comorbidities, e.g for weight, cardiovascular risk, sarcopaenia
Grading
High GRADE evidence rating for reduction of salt resulting in reduced blood pressure and albuminuria in patients with CKD.
Low GRADE rating for all other interventions and outcomes.