Natural history of uncomplicated urinary tract infection without antibiotics: a systematic review

Background Although uncomplicated urinary tract infection (UTI) is commonly treated with antibiotics, the duration of symptoms without their use is not established; this hampers informed decision making about antibiotic use. Aim To determine the natural history of uncomplicated UTI in adults. Design and setting Systematic review. Method PubMed was searched for articles published until November 2019, along with reference lists of articles identified in the search. Eligible studies were those involving adults with UTIs in either the placebo group of randomised trials or in single-group prognostic studies that did not use antibiotics and measured symptom duration. A modified version of a risk of bias assessment for prognostic studies was used. Outcomes were the percentage of patients who, at any time point, were symptom free, had symptom improvement, or had worsening symptoms (failed to improve). Adverse event data were also extracted. Results Three randomised trials (346 placebo group participants) were identified, all of which specified women only in their inclusion criteria. The risk of bias was generally low, but incomplete reporting of some details limited assessment. Over the first 9 days, the percentage of participants who were symptom free or reported improved symptoms was reported as rising to 42%. At 6 weeks, the percentage of such participants was 36%; up to 39% of participants failed to improve by 6 weeks. The rate of adverse effects was low and, in two trials, progression to pyelonephritis was reported in one placebo participant. Conclusion Although some uncertainty around the natural history of uncomplicated UTIs remains, some women appear to improve or become symptom free spontaneously, and most improvement occurs in the first 9 days. Other women either failed to improve or became worse over a variable timespan, although the rate of serious complications was low.