Fluid Intake Management in Maintenance Hemodialysis Using a Smartphone-Based Application: A Pilot Study.

RATIONALE & OBJECTIVE: Increased interdialytic weight gain (IDWG) has been associated with increased morbidity and mortality. We evaluated the usefulness and safety of a mobile application (app) that allows patients receiving maintenance hemodialysis to self-monitor their daily fluid intake.

STUDY DESIGN

Within group comparison before or during intervention.

SETTING & PARTICIPANTS: Patients receiving maintenance hemodialysis with mean IDWG of <4%.

EXPOSURE

Participants were trained to use a smartphone-based app, FiApp that allowed them to record fluid intake and compare with individual targeted daily fluid intake determined by the nephrologist.

OUTCOMES

The primary study outcome was the association between IDWG and fluid intake recorded in the FiApp. Secondary outcomes included FiApp safety and usage. Patient interviews were performed at weeks 1 and 4 to collect information regarding FiApp usability and recommendations for app improvements.

ANALYTICAL APPROACH

Mean, median, and standard deviation.

RESULTS

Eighteen of 25 patients completed the full 4-week study, provided all app data, and completed 2 patient interviews. The mean 4-week IDWG during app use was similar to the baseline mean 4-week IDWG before app use; however, 61% of the participants had a decrease in IDWG when using the app compared with IDWG at baseline. Of the 18 participants who completed the study, only 1 had a mean 4-week IDWG that was 20% higher than that at baseline. The app was used on ≥80% of the days by 13 (72%) of 18 participants, and was used every day in 7 (39%) of 18 participants. The mean relationship between fluid reported in the app and fluid consumed was 40%.

LIMITATIONS

This safety study recruited patients who had IDWG of <4%.

CONCLUSIONS

A smartphone-based app can be safely used to help patients receiving maintenance hemodialysis track and control fluid intake. Motivated patients were able to decrease IDWG despite baseline IDWG being <4% of the body weight.

TRIAL REGISTRATION

NCT03759847.

PLAIN-LANGUAGE SUMMARY: Patients receiving maintenance hemodialysis struggle to limit fluid intake. Excess fluid intake can lead to adverse cardiovascular events. We developed a smartphone app to help patients receiving dialysis self-monitor their fluid intake. In this safety study in patients receiving dialysis with an interdialytic weight gain of <4% of the body weight, more than half of the patients were able to decrease their interdialytic fluid intake while using the app, and only 1 patient had an increase in interdialytic weight gain of >20% while using the app. Information gleaned from structured patient interviews will be used to refine this app.