Design of clinical trials in patients with urinary tract infections.

This overview deals with the optimization of the design of clinical trials in patients with urinary tract infections (UTIs). Despite the fact that UTI is one of the most common types of infection and that the main end-point (elimination or persistence of bacteriuria) is objective and easy to register, the quality of studies performed and published has generally been less than optimal. Problems that should always be addressed in the study protocol are definitions of terms used, for example bacteriuria, level of the infection (cystitis or pyelonephritis), and uncomplicated and complicated infections; dimension of the patient's sample to allow adequate testing of a null hypothesis; procedures before, during and after treatment; methods for analysis of the results.