Treatment of asymptomatic UTI in older delirious medical in-patients: A prospective cohort study

Background: Despite clinical practice guidelines, asymptomatic bacteriuria (ASB) in older people is frequently treated. A common reason for treating ASB is a change in mental status. Objective: To determine how often asymptomatic UTI is treated in older medically ill delirious individuals and its association with functional recovery. Methods: Consecutive older medical in-patients were screened for delirium, and followed in hospital. Treatment for asymptomatic UTI was defined as documented treatment for a possible urinary tract infection with antibiotics, without concurrent infectious or urinary symptoms. The primary outcome was functional recovery at discharge or 3 months post-discharge. Poor functional recovery was defined by any one of death, new permanent long-term institutionalization or decreased ability to perform activities of daily living. Results: The study sample comprised 343 delirious in-patients, of which 237 (69%) had poor functional recovery. Ninety two (27%) delirious in-patients were treated for asymptomatic UTI. Treatment for asymptomatic UTI was associated with poor functional recovery compared to other delirious in-patients (RR 1.30, 95% CI: 1.14-1.48 overall). Similar results were seen when the analysis was restricted to only bacteriuric delirious individuals. Seven (7.5%) individuals treated for asymptomatic UTI developed Clostridium difficile infection compared to eight (3.2%) in the remainder of the delirious cohort (OR 2.45, 95% CI: 0.86-6.96). Conclusions: These results suggest that treatment of asymptomatic UTI in older medical in-patients with delirium is common, and of questionable benefit. Further research is needed to establish guidelines to minimize over-treatment of UTI in older delirious in-patients.