Introduction: Uncomplicated lower urinary tract infections (uLUTIs) are a frequent condition in primary care. Spanish clinical guidelines recommend a single 3 g dose of fosfomycin.To date, no clinical trial has directly compared short-course antibiotic treatments for uLUTI. This randomised clinical trial aims to compare the effectiveness of four short-course antibiotic regimens: a single 3 g dose of fosfomycin, two consecutive days of 3 g fosfomycin, 3 days of pivmecillinam 400 mg three times daily (t.i.d.), and 5 days of nitrofurantoin 100 mg t.i.d.

Methods: This multicentre, parallel-group clinical trial was conducted across four regions in Spain. Women (n=613) aged ≥18 years presenting with symptoms of uncomplicated lower urinary tract infection (uLUTI) and a positive urine dipstick were randomised to one of four treatment groups. Follow-up visits at days 7, 14, and 28 assessed clinical evolution. Urine samples were collected; cultures and, when positive, antibiograms for the three study antibiotics were performed. 

Results: Two treatment strategies, fosfomycin single and double dose, were dominated, being more costly and less effective (in terms of days with moderate or severe symptoms avoided) compared with nitrofurantoin. The mean cost per patient was 185.9€ for nitrofurantoin and 210.9€ for pivmecillinam. Considering a utility loss of 0.3149, associated with days of moderate or severe symptoms, pivmecillinam was associated with a higher cost and greater effectiveness, generating extra QALYs at a cost per QALY around 131,715€. Besides, each additional day of symptoms can be avoided at a cost of about 110€. Nitrofurantoin was therefore less costly but also less effective than pivmecillinam. 

Conclusion: Nitrofurantoin and pivmecillinam were the most cost-effective strategies. Although pivmecillinam was slightly more effective, its higher cost limited its economic advantage.

Laura Gallardo-Alfaro is a researcher at the Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain.