Effects of a Hypertension Management Mobile App on Urinary Sodium Excretion in Patients With Chronic Kidney Disease: Randomized Controlled Trial.

The smartphone app intervention did not significantly reduce estimated 24-hour urinary sodium excretion compared to control over 12 weeks.

• Mean change in estimated 24-hour urinary sodium excretion was 1.4 mmol (95% CI -12.0 to 14.7) in the intervention group vs 2.5 mmol (95% CI -10.7 to 15.6) in the control group.
• Between-group difference was -1.1 mmol (95% CI -19.8 to 17.7 mmol; P=.92).
• Analysis was conducted in the intention-to-treat population using a mixed-effects model for repeated measures.
• The intervention period was 12 weeks.
• Baseline mean (SD) estimated 24-hour urinary sodium excretion was 145 (33) mmol.

A significantly higher proportion of patients in the intervention group reported improved salt intake behaviors compared to the control group.

• 76% (35/46) of intervention group patients reported salt intake behaviors had 'significantly improved' or 'somewhat improved' vs 38% (18/47) of control group patients.
• The difference was statistically significant (P<.001).
• This self-reported behavioral improvement was not accompanied by a corresponding reduction in measured urinary sodium excretion.
• The improvement in self-reported behaviors did not alter outcomes even in the subgroup of patients reporting improved salt intake behaviors.

App engagement among intervention group patients was high throughout the 12-week study period.

• The median (IQR) app engagement rate was 96% (73%-99%).
• Engagement was calculated by dividing the number of days patients recorded blood pressure in the app by the total intervention period.
• The CureApp HT app delivered daily, individualized guidance tailored to each patient's lifestyle for hypertension management through lifestyle modifications and self-monitoring.

All key secondary outcomes were not significantly different between the intervention and control groups.

• Secondary outcomes included office blood pressure, brachial-ankle pulse wave velocity, urinary protein-to-creatinine ratio, and plasma brain natriuretic peptide.
• None of these outcomes differed significantly between groups during the 12-week intervention period.
• Secondary outcomes were not altered even in the subgroup of patients who reported improved self-reported salt intake behaviors.

The study enrolled patients with CKD who had both hypertension and elevated urinary sodium excretion at baseline.

• 101 patients with CKD were randomized: 51 to the intervention group and 50 to the control group.
• Eligibility required a history of hypertension and estimated 24-hour urinary sodium excretion of 100 mmol or greater.
• Mean (SD) baseline estimated glomerular filtration rate was 38 (18) mL/min/1.73 m².
• The trial was open-label, single-center, and randomized.
• Urinary sodium excretion was estimated from spot urine samples using the Tanaka method.

The authors identified an intention-behavior gap as the explanation for the discordance between self-reported behavioral improvement and objective salt intake measures.

• Despite 76% of intervention group patients self-reporting improved salt intake behaviors, no reduction in urinary sodium excretion was observed.
• The authors concluded that 'enhancing the intervention intensity may be necessary to effectively bridge the intention-behavior gap.'
• The findings suggest that self-reported salt intake behavior is not a reliable surrogate for actual salt intake in this population.