Efficacy Trial of a Mobile Application for Fluid Intake Management in Patients Receiving Chronic Hemodialysis Therapy

Increased interdialytic weight gain (IDWG) is associated with increased morbidity and mortality in patients receiving chronic hemodialysis. We evaluated the efficacy of a smartphone-based application (app) designed to support reductions in interdialytic fluid intake.

Pre-post intervention study.

Adult patients receiving chronic hemodialysis with mean IDWG >3.5% over a 3-month period were recruited from outpatient hemodialysis units in central North Carolina, United States.

Participants were trained to use a smartphone-based app that allowed recording fluid intake and incorporated behavioral support features (eg, goal setting, prompts, feedback). The patients were asked to use the app daily during the 8-week active phase of the trial.

The primary study outcome was the change in mean IDWG from baseline (before app usage) to the 8-week active phase. Secondary outcomes included app safety and usage. IDWG was also assessed during a 6-month passive phase to monitor for possible long-term behavioral changes.

Twenty-three patients completed the 8-week active phase and provided app data. Compared with baseline, mean IDWG for the 3-day interdialytic interval decreased by -0.52 ± 0.24 lb (P = 0.032) during the active phase and -0.86 ± 0.96 lb (P < 0.01) during the passive phase. No safety concerns (defined as >50% increase in IDWG) were observed. During the active phase, app was used on ≥80% of the days by 65% of participants and daily by 26% of participants. Reductions in IDWG were sustained during the passive phase. Correlations between app-recorded fluid intake and IDWG were weak and not statistically significant.

This uncontrolled pre-post study was subject to selection bias toward more technologically literate and adherent participants, did not meet recruitment targets, and lacked urine output data.

Use of a smartphone-based app designed to support fluid intake restriction is feasible and associated with sustained reductions in IDWG among patients receiving chronic hemodialysis, without safety concerns.