Antibiotics versus no treatment for asymptomatic bacteriuria in residents of aged care facilities: a systematic review and meta-analysis

BACKGROUND: Asymptomatic bacteriuria (ASB) is common among residents of residential aged care facilities (RACFs). However, differentiating between an established urinary tract infection and ASB in older adults is difficult. As a result, the overuse of dipstick urinalysis, as well as the subsequent initiation of antibiotics, is common in RACFs. AIM: To find, appraise, and synthesise studies that reported the effectiveness, harms, and adverse events associated with antibiotic treatment for older patients with ASB residing in RACFs. DESIGN AND SETTING: A systematic review using standard Cochrane methods of RACF residents with ASB using antibiotics against placebo, or no treatment. METHOD: Three electronic databases (PubMed, EMBASE, and CENTRAL), clinical trial registries, and forward–backward reference checks of included studies were searched. RESULTS: Nine randomised controlled trials, comprising 1391 participants were included; two of which used a placebo comparator, and the remaining seven used no therapy control groups. There was a relatively small number of studies assessed per outcome and an overall moderate risk of bias. Outcomes related to mortality, development of ASB, and complications were comparable between the two groups. Antibiotic therapy was associated with a higher number of adverse effects (four studies; 303 participants; risk ratio [RR] 5.62, 95% confidence interval [CI] = 1.07 to 29.55, P = 0.04) and bacteriological cure (nine studies; 888 participants; RR 1.89, 95% CI = 1.08 to 3.32, P = 0.03). CONCLUSION: Overall, although antibiotic treatment was associated with bacteriological cure, it was also associated with significantly more adverse effects. The harms and lack of clinical benefit of antibiotic use for older patients in RACFs may outweigh the benefits.