Hydrophilic catheters: an evidence-based analysis

To review the evidence on the effectiveness of hydrophilic catheters for patients requiring intermittent catheterization.

There are various reasons why a person would require catheterization, including surgery, urinary retention due to enlargement of the prostate, spinal cord injuries, or other physical disabilities. Urethral catheters are the most prevalent cause of nosocomial urinary tract infections, that is, those that start or occur in a hospital. A urinary tract infection (UTI) occurs when bacteria adheres to the opening of the urethra. Most infections arise from Escherichia coli, from the colon. The bacteria spread into the bladder, resulting in the development of an infection. The prevalence of UTIs varies with age and sex. There is a tenfold increase in incidence for females compared with males in childhood and throughout adult life until around 55 years, when the incidence of UTIs in men and women is equal, mostly as a consequence of prostatic problems in men. Investigators have reported that urethritis (inflammation of the urethra) is found in 2% to 19% of patients practising intermittent catheterization.

Hydrophilic catheters have a polymer coating that binds o the surface of the catheter. When the polymer coating is submersed in water, it absorbs and binds the water to the catheter. The catheter surface becomes smooth and very slippery. This slippery surface remains intact upon insertion into the urethra and maintains lubrication through the length of the urethra. The hydrophilic coating is designed to reduce the friction, as the catheter is inserted with the intention of reducing the risk of urethral damage. It has been suggested that because the hydrophilic catheters do not require manual lubrication they are more sterile and thus less likely to cause infection. Most hydrophilic catheters are prepackaged in sterile water, or there is a pouch of sterile water that is broken and released into the catheter package when the catheter is ready to use.

The Medical Advisory Secretariat searched for reports of systematic reviews of randomized controlled trials (RCTs), meta-analyses of RCTs, and RCTs. The following databases were searched: Cochrane Library International Agency for Health Technology Assessment (fourth quarter 2005), Cochrane Database of Systematic Reviews (fourth quarter 2005), Cochrane Central Register of Controlled Trials (fourth quarter 2005), MEDLINE (1966 to the third week of November 2005), MEDLINE In-Process and Other Non-indexed Citations (1966 to November 2005), and EMBASE (1980 to week 49 in 2005). Search terms were urinary catheterization, hydrophilic, intermittent, and bladder catheter. The Medical Advisory Secretariat also conducted Internet searches of Medscape (www.medscape.com) for recent reports on trials that were unpublished but presented at international conferences. In addition, the Web site Current Controlled Trials (www.controlled-trials.com) was searched for ongoing trials on urinary catheterization.

Five RCTs were identified that compared hydrophilic catheters to standard catheters. There was substantial variation across the studies in terms of the reason for catheterization, inclusion criteria, and type of catheter used. Two studies used reusable catheters in the control arm, while the other 3 RCTs used single-use catheters in the control arm. All 5 RCTs focused mainly on males requiring intermittent catheterization. Age varied considerably across studies. One study consisted of young males (mean age 12 years), while another included older males (mean age 71 years). The RCTs reported conflicting results regarding the effectiveness of the hydrophilic catheters compared with standard catheters in terms of rates of UTIs. All 5 RCTs had serious limitations. Two of the studies were small, and likely underpowered to detect significant differences between groups. One RCT reported 12-month follow-up data for all 123 patients even though more than one-half of the patients had dropped out of the study by 12 months. Another RCT had unequal groups at baseline: the patients in the hydrophilic group had twice the mean number of UTIs at baseline compared with the standard catheter group. The fifth RCT used catheters to treat patients with bladder cancer; therefore, the results of their study are not generalizable to the population requiring intermittent catheterization. Two studies did not find significant differences between the hydrophilic and standard catheter groups for patient satisfaction. Another RCT reported conflicting results; however, the overall opinion of the catheters was not significantly different between the treatment groups. A fourth RCT found that the hydrophilic catheters were substantially more comfortable than standard catheters. The fifth RCT did not report results for quality of life or patient satisfaction. Similar to the results for effectiveness, it is not possible to clearly establish if there is a significant difference in patient satisfaction between the patients using hydrophilic catheters and those using standard catheters.

Patients requiring intermittent catheterization use, on average, 4 to 5 intermittent catheters per day. Patients admitted to hospitals using intermittent catheters typically do not reuse catheters, owing to the potential increased risk of infection in hospital. Patients self-catheterizing at home are more likely to reuse catheters. Standard catheters cost about $1.00 to $1.50/catheter. Hydrophilic catheters cost about $2.00 to $5.00/catheter, depending on the type and whether they have antibiotics inside. All hydrophilic catheters are single-use. At this time there is insufficient evidence to indicate whether hydrophilic catheters are associated with a lower rate of UTIs and improved patient satisfaction among people requiring intermittent catheterization.