Aim: to assess whether the volume of fluid intake influence the prevention of urinary stone formation.
Methods: a systematic review from MEDLINE Electronic database was conducted. All of the controlled trial (RCT), case-control, and cohort studies written in English language were included in the study. Data analysis was performed to the design of the study, volume of fluid intake (higher volume as experimental group and lower volume as control group), and risk of stone formation. All of the included studies were appraised using the Oxford Center for Evidence-based Medicine appraisal tool for therapy (Randomized Controlled Trial) and level of evidence.
Results: our systematic review included five studies (1 RCT and case-control study in patients with history of urolithiasis, and 3 prospective cohorts in patients without history of urolithiasis). Three studies increased fluid intake to 2.5 Liters/day and one study to 2 Liters/day, while one other study used the urine production target of 2 Liters/day. All of these studies showed that increased fluid intake per day could decrease the risk of both primary and secondary stone formation.
Conclusion: stronger evidence are still needed to conclude that increasing fluid intake could be utilized as a strategy to prevent primary urolithiasis because of the lack of data from the clinical trials supporting it. However, to prevent the recurrence of urolithiasis, increasing fluid intake could be recommended with the urine volume target of more than 2,000 mL/day.