The authors note that UTIs, and consequently recurrent UTIs, are over-diagnosed in older people. Although previous meta-analyses have shown benefit for antibiotic prophylaxis, analyses have included data from mostly small trials of younger women without comorbidities. There is therefore uncertainty around the generalisability of these findings to older adults.
The search was for randomised controlled trials published in English, comparing long-term antibiotics (>6 months) versus placebo or other non-antibiotic interventions on the rate of UTI in older adults (aged over 65 years) with recurrent UTI. Only three relevant studies were located; these were relatively small, of limited quality and short-term (evaluating the intervention over 6-12 months), and only included women. Two different antibiotics were evaluated (co-trimoxazole in 2 studies; nitrofurantoin in 1 study) and the comparators also differed (capsule of lactobacilli; oestrogen pessaries; D-mannose powder).
When pooled using random-effects meta-analysis, long-term antibiotic therapy was found to reduce the risk of a woman experiencing a UTI during the prophylaxis period (pooled RR 0.76; 95% CI 0.61 to 0.95). This means that about eight post-menopausal women need treatment with long-term antibiotics to prevent one woman experiencing a UTI during the prophylaxis period.
Only one trial measured the impact of long-term antibiotics on antibiotic resistance; this showed a dramatic increase in urinary and faecal isolates that were resistant to the antibiotic used.
There are a lack of data on antibiotic prophylaxis in older men and in nursing home residents, and the available data discussed above in older women have various limitations. Uncertainty therefore remains about the benefits and harms of long-term antibiotics in these populations, and further research is required to address unanswered questions regarding long-term effects, duration of use, adverse effects and antibiotic resistance.