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

Background: Asymptomatic bacteriuria (ASB) is common amongst 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 synthesize studies that reported the effectiveness, harms and adverse events associated with antibiotics treatment for elderly patients with ASB residing in RACFs. Design and setting: A systematic review, using standard Cochrane methods of RACF residents with asymptomatic bacteriuria using antibiotics against placebo, or no treatment. Method: We searched three electronic databases (PubMed, Embase, CENTRAL), clinical trial registries and citing-cited references of included studies. 
Results: Nine randomised controlled trials, comprising 1,391 participants were included; 2 of which used a placebo comparator, and the remaining 7 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 (4 studies; 317 participants; Relative Risk (RR)=5.62, 95% CI: 1.07-29.55, p=0.04) and bacteriological cure (9 studies; 888 participants; RR=1.89, 95% CI: 1.08-3.32, p<0.001). 
Conclusion: Overall, whilst the 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 its benefits.