RESUMO
PURPOSE: Overactive bladder imposes a significant socioeconomic burden on the health care system. It is a commonly held belief that increased fluid intake (8 glasses of water per day) is beneficial for health. However, increased fluid intake exacerbates overactive bladder symptoms. Thus, it is imperative that clinicians appropriately educate patients for whom increased water intake may be detrimental (women with overactive bladder), in contrast to patients with comorbidities that necessitate increased water intake (nephrolithiasis). We systematically reviewed the literature to determine the potential health advantages of increased water intake and identify specific subpopulations that need increased hydration. MATERIALS AND METHODS: We systematically reviewed published articles from 1972 through 2017 on PubMed® and the Cochrane Library. The data were reviewed independently by 2 individuals. Studies were included if they explored water intake in relation to the risk of a particular disease. RESULTS: Level 1 evidence supported increased fluid intake in patients with nephrolithiasis. There was no available evidence to support increased fluid intake in patients with cardiovascular disease, constipation, venous thromboembolism, headaches, cognitive function or bladder cancer. Dehydration may exacerbate some conditions, specifically chronic constipation and headache intensity. Increased fluid intake may have a role in preventing stroke recurrence but not in preventing primary stroke. CONCLUSIONS: The available reviewed literature suggests no benefit to drinking 8 glasses of water per day in patients without nephrolithiasis. Also, excess fluid intake can exacerbate symptoms of overactive bladder.