Choice of empirical antibiotic therapy and adverse outcomes in older adults with suspected urinary tract infection: cohort study

Background Nitrofurantoin is widely recommended for empirical treatment of urinary tract infection (UTI) but primary care clinicians may prescribe alternative antibiotics to improve prognosis in older, sicker patients. We assessed if prescribing alternative antibiotics was associated with reduced risk of adverse outcomes in older patients. Methods This retrospective cohort study included patients aged ?65 years empirically treated for a UTI with nitrofurantoin, cefalexin, ciprofloxacin or co-amoxiclav. We matched patients on their propensity to receive a nitrofurantoin prescription and used mixed effects logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) for re-consultation and re-prescription (proxy for treatment failure), hospitalisation for UTI, sepsis, or acute kidney injury (AKI), and death. Results We identified 42,298 patients aged ?65 years prescribed empirical nitrofurantoin, cefalexin, ciprofloxacin or co-amoxiclav for a UTI. Compared to nitrofurantoin, patients prescribed cefalexin, ciprofloxacin or co-amoxiclav had lower odds of re-consultation and re-prescription (OR for cefalexin; 0.85 95% CI 0.75-0.98; OR for ciprofloxacin; 0.48, 95% CI 0.38-0.61, OR for co-amoxiclav; 0.77, 95% CI 0.64-0.93). Patients prescribed cefalexin or ciprofloxacin had greater odds of hospitalisation for sepsis (OR for cefalexin; 1.89, 95% CI 1.03-3.47; OR for ciprofloxacin 3.21, 95% CI 1.59 ? 6.50), and patients prescribed cefalexin had greater odds of death (OR 1.44, 95% CI 1.12-1.85). Conclusions Compared to nitrofurantoin, prescribing of alternative antibiotics for UTI in older people may be associated with lower rates of treatment failure but was not associated with reduced risk of UTI-related hospitalisation or death.