Sodium Restriction in Patients With CKD: A Randomized Controlled Trial of Self-management Support

Abstract

Background: To evaluate the effectiveness and sustainability of self-managed sodium restriction in patients with chronic kidney disease.

Study design: Open randomized controlled trial.

Setting & participants: Patients with moderately decreased kidney function from 4 hospitals in the Netherlands.

Intervention: Regular care was compared with regular care plus an intervention comprising education, motivational interviewing, coaching, and self-monitoring of blood pressure (BP) and sodium.

Outcomes: Primary outcomes were sodium excretion and BP after the 3-month intervention and at 6-month follow-up. Secondary outcomes were protein excretion, kidney function, antihypertensive medication, self-efficacy, and health-related quality of life (HRQoL).

Results: At baseline, mean sodium excretion rate was 163.6±64.9 (SD) mmol/24 h; mean estimated glomerular filtration rate was 49.7±25.6mL/min/1.73m²; median protein excretion rate was 0.8 (IQR, 0.4-1.7) g/24 h; and mean 24-hour ambulatory systolic and diastolic BPs were 129±15 and 76±9mmHg, respectively. Compared to regular care only (n=71), at 3 months, the intervention group (n=67) showed reduced sodium excretion rate (mean change, -30.3 [95% CI, -54.7 to -5.9] mmol/24 h), daytime ambulatory diastolic BP (mean change, -3.4 [95% CI, -6.3 to -0.6] mmHg), diastolic office BP (mean change, -5.2 [95% CI, -8.4 to -2.1] mmHg), protein excretion (mean change, -0.4 [95% CI, -0.7 to -0.1] g/24h), and improved self-efficacy (mean change, 0.5 [95% CI, 0.1 to 0.9]). At 6 months, differences in sodium excretion rates and ambulatory BPs between the groups were not significant, but differences were detected in systolic and diastolic office BPs (mean changes of -7.3 [95% CI, -12.7 to -1.9] and -3.8 [95% CI, -6.9 to -0.6] mmHg, respectively), protein excretion (mean changes, -0.3 [95% CI, -0.6 to -0.1] g/24h), and self-efficacy (mean change, 0.5 [95% CI, 0.0 to 0.9]). No differences in kidney function, medication, and HRQoL were observed.

Limitations: Nonblinding, relatively low response rate, and missing data.

Conclusions: Compared to regular care only, this self-management intervention modestly improved outcomes, although effects on sodium excretion and ambulatory BP diminish over time.

Keywords: Behavior change; blood pressure; chronic kidney disease (CKD); dietary sodium intake; disease progression; health-related quality of life (HRQoL); hypertension; kidney function; lifestyle interventions; modifiable risk factor; nutrition; protein excretion; randomized controlled trial; self-efficacy; self-managment support.