A Randomized Trial Evaluating the Use of a Smart Water Bottle to Increase Fluid Intake in Stone Formers

Abstract

The aim of this study is to evaluate if the use of a smart water bottle improves urine volume in stone forming patients. Adults with nephrolithiasis and low urine volume (<1.5L) documented on a 24-hour urinalysis (24hr U) were randomized to receive either standard dietary recommendations to increase fluid intake (DR arm), or DR and a smart water bottle (HidrateSpark®; Hydrate Inc., Minneapolis, MN) that recorded fluid intake, synced to the user's smartphone, and provided reminders to drink (SBarm). Participants completed baseline surveys assessing barriers to hydration. They then repeated a 24hr U and survey at 6 and 12weeks, respectively. Eighty-five subjects (44 DR, 41 SB) were enrolled. The main baseline factor limiting fluid intake was not remembering to drink (60%). Follow-up 24hr Us were available for 51 patients. The mean increase in volume was greater in the SB arm (1.37L, 95% confidence interval -0.51 to 3.25) than the DR arm (0.79L, 95% confidence interval -1.15 to 2.73) (P=.04). A smaller percentage of subjects in the SB arm reported not remembering to drink as the main factor limiting fluid intake in the follow-up questionnaire compared to baseline (45.4% vs. 68.4%, P<.05). This was not true for the DR arm (40.0% vs. 51.2%, P=.13). Difficulty remembering to drink is a barrier to achieving sufficient fluid intake in stone formers. The use of a smart bottle was associated with greater increases in 24hr U volumes and less difficulty remembering to drink.