| dc.description.abstract | Background & Aims: Current guidelines advise sodium restriction in all patients with chronic
kidney disease (CKD). However, there is no direct evidence linking sodium intake to increased
mortality. This study aims to investigate the relationship between sodium intake and mortality in
CKD patients.
Methods: A retrospective cohort analysis, using routine clinical data from electronic healthcare
records. Sodium intake was estimated by 24-hour urinary sodium excretion. Patients with a
GFR of 15 to 60, with at least one 24-hour sodium excretion, visiting an outpatient clinic for
dietetics and cardiovascular risk management were included. The association between sodium
intake and mortality was investigated in two manners: 1) sodium intake as a continuous
determinant; 2) sodium intake categorized as: low (i.e. < 100 mmol/day), middle (i.e. 100-200
mmol/day), and high (i.e. >200 mmol/day) intake. Cox proportional hazard analysis, adjusted for
patient characteristics, kidney function and cardiovascular risk factors, was used to calculate
hazard ratios time-varying sodium intake.
Results: In total, 3787 patients were included. 1268 patients were low-intake, 1966patients were
mid-intake, 553 patients were high intake. Less than 33.5% of patients had a sodium intake
below 100 mmol (equivalent to 5 grams of salt) per day. In the low sodium intake group, 38% of
patients died, versus 22.1% in the high intake group. The corrected hazard ratios for mortality
were 0.63 (95% CI: 0.55 – 0.72) for medium sodium intake and 0.68 (95% CI: 0.55 – 0.83) for
high sodium intake. This hazard ratio accounts for varying levels of sodium intake over time.
Conclusions
Very low sodium intake is correlated with mortality, irrespective of kidney function. Furthermore,
adherence to sodium guidelines is not possible for most patients. Sodium restriction should not
be prescribed to all CKD patients. Rather, a personalised approach should be taken by doctors,
dieticians, and patients. | |
