Effectiveness of Fluid and Caffeine Modifications on Symptoms in Adults With Overactive Bladder: A Systematic Review

Overactive bladder (OAB) is prevalent in men and women and negatively impacts physical and psychological health. Fluid and caffeine intake modifications, which are lifestyle modification interventions, are simple methods to manage OAB. However, studies that synthesized both interventions and found scientific evidence are scarce. This review aimed to synthesize scientific evidence on whether fluid and caffeine intake modifications are effective for OAB symptoms. PubMed, CINAHL (Cumulative Index for Nursing and Allied Health Literature), Embase, Scopus, the Cochrane Library, KoreaMed, and RISS (Research Information Sharing Service) were used to search for studies and 8 studies were included. The Cochrane risk of bias tool (RoB 2.0) and ROBINS-I (Risk Of Bias In Non-randomized Studies - of Interventions) were used to assess the quality of selected studies. Due to the heterogeneous outcome variables, a meta-analysis was not conducted. Among the 8 included, 7 studies were randomized controlled trials and one was a quasi-experimental study. Four studies assessed urgency. Caffeine reduction was statistically effective for urgency symptoms, but increasing fluid intake was not. Frequency was assessed in 5 studies, which showed decreasing caffeine and fluid intake was effective in treating the symptoms. Urinary incontinence episodes were assessed in 6 studies, and nocturia in 2. Restricting caffeine intake was effective in treating these 2 symptoms, but restricting both caffeine and fluid intake was not. Quality of life (QoL) was examined in 5 studies, and modifying fluid and caffeine intake significantly improved QoL in 2. Although there were limited studies, our review provides scientific evidence that fluid and caffeine intake modification effectively manages OAB symptoms. Further research should examine acceptability and sustainability of interventions in the long-term and enable meta-analysis.