Another approach used to reduce the incidence of UTI associated with catheterization in patients with neurogenic bladder involves the application of coatings to the catheter (Giannantoni et al. 2001; Vapnek et al. 2003; De Ridder et al. 2005; Cardenas & Hoffman 2009; Cardenas et al. 2011). For example, Giannantoni et al. (2001) employed a double-blind, crossover RCT design (n=18) to examine the difference between a pre-lubricated, nonhydrophilic Instantcath catheter as compared to a conventional polyvinyl chloride (PVC) silicon-coated Nelaton catheter with respect to the occurrence of UTIs and urethral trauma. The subjects were randomized to 1 of 2 groups which tried each catheter for a period of 7 weeks in an A-B, B-A design. Both incidence of UTIs (p=0.3) and presence of asymptomatic bacteriuria (p=0.024) were significantly reduced for the pre-lubricated catheter versus the conventional PVC catheter. Perhaps most interesting, three subjects requiring assistance with the conventional catheter became independent with the pre-lubricated catheter, although it was not reported if these individuals were in the group using the conventional catheter initially or lastly. The existence of an order effect (or not) for any of the measures was not reported. In terms of general satisfaction with use, subjects rated the pre-lubricated catheter significantly higher than the conventional catheter with respect to comfort, ease of inserting and extracting, and handling.
A similar finding of reduced incidence of UTIs (p=0.02) was reported by De Ridder et al. (2005), but in this case the reduction was associated with a hydrophilic catheter as compared to the conventional PVC catheter. This multi-centre investigation also employed a RCT design (N=123) but had several methodological problems that likely constrained the potential utility of the results. Most significant was a high drop-out rate (54%) with slightly more individuals not completing the study from the hydrophilic catheter group. A probable cause for many of these drop-outs was the lengthy treatment period of 1 year during which many individuals were likely to improve bladder function such that intermittent catheterization was no longer required. There were no other significant differences noted between the two groups including the number of bleeding episodes or occurrence of hematuria, leukocyturia and bacteriuria. More individuals expressed greater satisfaction with various aspects of the hydrophilic catheter, although these differences were also not significant. A reduced incidence of hematuria and a significant decrease in UTI incidence was also reported by Vapnek et al. (2003), when hydrophilic versus non-hydrophilic catheter use was compared in a 12 month study of 62 patients (n=49 completed).
Reduced numbers of treated UTIs were reported by Cardenas and Hoffman (2009) with the use of hydrophilic catheters versus standard nonhydrophlic catheters even though no difference was reported between the 2 groups of self-IC SCI patients for number of symptomatic UTIs. Furthermore, lubrication was more beneficial for men since women on self-IC were more likely to develop UTIs regardless of catheter type. Although this study may have been underpowered, it is important to note that the drop out rate was just under 20% as compared to almost 54% in the DeRidder et al. (2005) study with only 57/123 subjects remaining at the end of year 1. Cardenas and Hoffman (2009) also included women which allowed for potential gender differentiation in the effect of hydrophilic catheter use. Although females accounted for 29% of the participants, a sample size of should invoke caution when interpreting the data.
More recently, Cardenas et al. (2011) showed that time to the first antibiotic-treated symptomatic UTI in acute SCI patients (less than 3 months injured for inclusion) could be delayed by opting for a hydrophilic coated catheter as compared to an uncoated catheter. However effects disappeared when first months after institutional discharge were included in the analysis. Participants and/ or caregivers reported significantly higher satisfaction (P=0.007) with the hydrophilic coated catheter versus the uncoated however no differences were found in a similar evaluation by nursing staff. This is largest RCT to date on this topic.
There is level 1b evidence (from one RCT; Giannantoni et al. 2001) that, compared to conventional poly vinyl chloride catheters, pre-lubricated non-hydrophilic catheters are associated with fewer UTIs and reduced urethral bleeding.
There is level 2 evidence (from one RCT; De Ridder et al. 2005) that, compared to conventional poly vinyl catheters, hydrophilic catheters may be associated with fewer UTIs, but not necessarily urethral bleeding.
There is level 2 evidence (from two RCTs; Cardenas & Hoffman 2009; Cardenas et al. 2011) that use of hydrophilic versus non-hydrophilic catheters are associated with fewer symptomatic UTIs treated with antibiotics even though the number of symptomatic UTIs are similar between groups.
A reduced incidence of UTIs or reduced antibiotic treatment of symptomatic UTIs have been associated with pre-lubricated or hydrophilic catheters as compared to standard non-hydrophilic catheters.