A Cochrane review [withdrawn from publication] included 31 studies, of which 13 were RCTs and 18 cross-over trials. The review compared sterile versus clean catheterisation technique, differents types of catheters and materials, coated (pre-lubricated) versus uncoated (separate lubricant) catheters, single (sterile) or multiple use (clean) catheters, self-catheterisation versus catheterisation by others, and any other strategies designed to reduce urinary tract infections (UTIs) in respect of incidence of symptomatic UTI, haematuria, other infections and user preference, in adults and children using intermittent catheterisation for incomplete bladder emptying. Most studies were small (less than 60 participants), although 5 trials had more than 100 participants. Where there were data, confidence intervals around estimates were wide and hence clinically important differences in UTI and other outcomes could neither be identified nor ruled out reliably.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment and more than 20% loss to follow up in several studies), by inconsistency (heterogeneity in outcomes; considerable variation in length of follow-up and definitions of UTI), by imprecise results (few patients and wide confidence intervals) and by indirectness (several studies were more than ten years old and outcome measures varied between studies; colonization without symptoms is not treated in intermittent catheterisation users nowadays).