Hydrophilic Catheters Versus Noncoated Catheters for Reducing the Incidence of Urinary Tract Infections: A Randomized Controlled Trial

Article Outline

• Abstract
• Methods
  • Subjects
  • Study Design
  • Procedures
  • Statistical Analysis
• Results
• Discussion
  • Study Limitations
• Conclusions
• References
• Copyright

Abstract 

Cardenas DD, Hoffman JM. Hydrophilic catheters versus noncoated catheters for reducing the incidence of urinary tract infections: a randomized controlled trial.

Objective

To test the hypotheses that hydrophilic catheters reduce the incidence of symptomatic urinary tract infections (UTIs) in persons with spinal cord injury on self–intermittent catheterization (IC).

Design

Randomized controlled trial.

Setting

Community.

Participants

Subjects (N=56) on IC with recurrent UTIs and who met eligibility criteria.

Intervention

Use of hydrophilic catheters for IC.

Main Outcome Measure

Symptomatic UTIs treated with antibiotics.

Results

Of the 56 subjects enrolled, 45 completed the study (22 in the treatment group, 23 in the control group). There were no significant differences in demographics, including sex, between the treatment group and the controls except for more tetraplegic subjects in the control group (P<.05). Seventy-one percent of the treatment group and 52% of the control group were men. The total number of symptomatic UTIs treated with antibiotics was significantly smaller in the treatment group than in the control group (P<.05). Seventy percent of the control group had at least 1 antibiotic treatment episode compared with only 50% of those with the hydrophilic catheter (P=.18). There was no significant difference in the incidence of bacteriuria or symptomatic UTIs among the 2 groups. Level of injury and years with injury were unrelated to symptomatic UTIs, but being female increased the risk of UTIs (P<.01).

Conclusions

Although there was no difference in the number of symptomatic UTIs in the 2 groups, hydrophilic catheter usage was associated with reduced numbers of treated UTIs as compared with standard nonhydrophilic catheters in persons with spinal cord injury who used self-IC; however, the study is limited by a small sample size. Women on self-IC were more likely to develop UTIs regardless of the catheter type, suggesting that the benefits of the lubrication may be more important in men.

Key Words: Rehabilitation, Spinal cord injuries, Urinary catheterization, Urinary tract infections

List of Abbreviations: IC, intermittent catheterization, SCI, spinal cord injury, UTI, urinary tract infection

URINARY TRACT INFECTION is reported to be the most frequent medical complication during initial medical rehabilitation after SCI, occurring in most such people¹ and continuing to be a common cause of morbidity throughout the lifetime of many people with SCI.² The overall rate of UTIs in people with SCI is about 2.5 episodes per patient per year.³ UTI may, in many instances, produce mild to moderate illness that can be managed on an outpatient basis. However, UTI has been reported as the leading cause of rehospitalization after SCI.⁴ Thus, prevention of UTI remains one of the primary goals of neurogenic bladder management after SCI.

IC has become the standard of care for SCI, particularly in those patients who have adequate manual dexterity to perform self-IC.⁵ IC is favored over chronic indwelling catheterization because of evidence that it decreases the incidence of UTI,⁶ as well as other adverse outcomes of chronic indwelling catheterization such as bladder stones, renal stones, epididymitis, hydronephrosis, and bladder cancer.⁷

Although self-IC reduces the risk of UTI compared with indwelling catheters, the risk is still present, and efficacious methods to prevent UTIs are needed. Low-friction hydrophilic catheters were introduced in 1983 to reduce catheter-related complications and have demonstrated the potential to reduce UTIs in persons who used IC.⁸ Hydrophilic catheters are coated along the entire length with a hydrophilic substance, primarily polyvinyl-pyrrolidone, which, when combined with water, produces a smooth, slippery surface that has 10- to 15-fold less friction than a standard polyvinyl catheter.⁹ Vaidyanathan et al¹⁰ found that the degree of urethral inflammatory response, determined by urethral cytology in patients with spinal cord disorders on clean IC, was significantly lower when patients used the hydrophilic catheter rather than noncoated polyvinyl catheters. Urethral cytology also revealed a significantly greater number of bacteria in those who used noncoated catheters.

Three parallel group trials compared a hydrophilic catheter to an uncoated catheter and reported data on UTIs.⁸, ⁹, ¹¹ Sutherland et al¹² randomized 33 boys with neurogenic bladder who were using IC to either the hydrophilic catheter or to a noncoated catheter and followed them for 8 weeks. Episodes of microscopic hematuria were significantly fewer in the hydrophilic group (P<.05) than in the noncoated catheter group, but no difference was found in the incidence of UTIs. A randomized controlled multicenter study comparing the hydrophilic catheter to conventional catheters in 62 outpatients with neurogenic bladders over the course of 12 months, with 49 competing the study, failed to demonstrate a significant difference in the number of UTIs; however, there was a significant decrease in the UTI rate from baseline in the hydrophilic group but not in controls.¹¹ In a 1-year multicenter study of 123 male patients with SCI,¹³ fewer people reported a UTI treated with antibiotics in those who used a hydrophilic catheter compared with those who used uncoated catheters. Results were marginally significant (39 of 61 [64%] vs 51 of 62 [82%]; relative risk, .78; 95% confidence interval, .62–.97).¹³, ¹⁴ Nevertheless, the median number of UTIs per 1000 catheter-days in the hydrophilic group was lower (5.4, n=61), but not significantly so, compared with the standard catheter group (8.1, n=61).

Thus, there is still no clear evidence that hydrophilic catheters reduce the incidence of UTIs in adults with SCI and recurrent UTIs.

The objective of this study was to test the hypothesis that use of a hydrophilic catheter reduces the incidence of symptomatic UTIs as compared with a standard noncoated catheter in patients with chronic SCI and recurrent UTIs. Although asymptomatic bacteriuria is a common finding in persons on IC, we also hypothesized that the hydrophilic catheter would reduce the prevalence of asymptomatic bacteriuria.

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Methods 

Subjects 

Subjects were solicited through advertisement in local newspapers, notices in Seattle-area clinics serving patients with SCI, and announcements through the newsletter of the Northwest Regional Spinal Cord Injury System, a comprehensive, interdisciplinary model system funded in part by the National Institute on Disability and Rehabilitation Research, United States Department of Education.

Study inclusion criteria were as follows: (1) SCI 6 months or more ago, (2) self-reported history of 2 or more UTIs during the past year, (3) use of IC with a noncoated catheter and an open system, (4) no plan to change the method of bladder drainage during the study period, (5) naive to hydrophilic catheters, and (6) at least 18 years of age. The University of Washington Human Subjects Review Committee approved the study protocol, and each subject gave written informed consent. Subjects were excluded if they had evidence of upper urinary tract abnormalities or renal or bladder calculi in a screening renal ultrasound.

Study Design 

The study was a randomized, controlled trial of a hydrophilic catheter for the prevention of UTIs in persons with SCI. Fifty-six subjects were randomly assigned to either the LoFric^a hydrophilic catheter group or to the control group. Of the 56 subjects enrolled, 45 completed the study. All but 1 subject with C4 American Spinal Injury Association Impairment Scale grade A SCI had adequate hand function and were able to perform self-catheterization on a routine basis. A total of 11 subjects withdrew from the study, 1 dropped at the subject's request, 3 were lost to follow-up, 3 were discontinued as a result of placement of an indwelling Foley catheter, 3 withdrew as a result of nonurologic medical complications, and 1 withdrew as a result of developing renal stones. Of the 45 subjects who completed the study, 22 were randomized to the hydrophilic catheter and 23 to the control group. The control group continued using their usual noncoated catheter with clean technique, but used a new catheter with each catheterization throughout the study. Participation in the study continued for 1 year. Figure 1 shows participation allocation.

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• Fig 1. 

  Flow diagram showing participant allocation.

Procedures 

After providing informed consent, all subjects underwent a neurologic examination to determine the level of SCI and completeness of the lesion using the International Standards for the Neurological and Functional Classification of Spinal Cord Injury¹⁵ (table 1). Subjects completed a sociodemographic, equipment, and usual catheterization procedure questionnaire. In addition, subjects provided an initial catheterized urine sample for urinalysis and culture and sensitivity testing. Any subject found to have significant bacteriuria, defined as 10⁵ cfu/mL or more, was not enrolled until after appropriate antibiotic treatment to ensure that subjects were not enrolled with ongoing bacteriuria. A symptomatic UTI was defined as significant bacteriuria (≥10⁵ cfu/mL) plus at least 1 sign or symptom suggestive of UTI. Subjects were also asked to complete an inventory of UTI symptoms including pain or discomfort over the kidney or bladder, or during urination, onset of urinary incontinence, fever, increased spasticity, autonomic hyperreflexia, cloudy or foul-smelling urine, and feeling sick, tired, or uneasy.

Table 1. Demographic and Outcome Variables

Characteristics	Values	Treatment (n=22)	Control (n=23)	P
Demographics
Mean age ± SD (y)		42.3±10.4	40.1±9.3
Sex, n (%)	Men	17(77)	12(52)
	Women	5(23)	11(48)
Education, n (%)	High school or less	5(23)	3(13)
	Some college	17(77)	20(87)
Employment status, n (%)	Employed	8(36)	9(39)
	Not employed	11(50)	12(52)
	Student	3(14)	2(9)
Ethnicity, n (%)	White	16(73)	22(96)	.05
	Nonwhite	6(27)	1(4)
Paralysis level, n (%)	Tetraplegia	5(23)	12(52)	.05
	Paraplegia	17(77)	11(48)
AIS (n)	C4–C8: grade A	2	8
	C4–C8: grade B–D	3	4
	T6–L5: grade A	13	5
	T6–L5: grade B–D	4	6
Time since injury (y)		15.2±10.5	16.1±14.7
Outcome⁎
Total UTIs (1y)		1.18±1.3	1.00±1.0	.61
Total antibiotic treatment episodes (1y)		0.77±0.87	1.65±1.46	.02
Subjects who had at least 1 UTI, n (%)		12(54)	14(61)	.67
Subjects who had at least 1 antibiotic treatment episode, n (%)		11(50)	16(70)	.18

NOTE. Values are mean ± SD unless otherwise indicated.

Abbreviation: AIS, American Spinal Injury Association Impairment Scale.

After randomization, a nurse experienced with catheterization techniques instructed those randomized to the hydrophilic catheter in its use and instructed those in the control group in proper clean technique. Urine was then collected once a month for the first 3 months and then at months 6, 9, and 12. All subjects provided a catheterized specimen taken after discarding the first 40 to 50mL and using clean technique. Throughout the study period, the same inventory of UTI symptoms was collected on a monthly basis to determine whether any symptomatic UTIs may have occurred and if antibiotics had been prescribed. All subjects were asked to visit their regular health care provider as they would normally for the treatment of any symptomatic UTIs that they developed during the course of the study.

Statistical Analysis 

Initial power analysis conducted before beginning the study resulted in a goal of 30 subjects in each treatment arm, which should be sufficient to detect a 2-point difference in our primary outcome measure, symptomatic UTIs, with an alpha of .05 and power of 80%. Criteria for inclusion was a history of 2 more UTIs during the past 1 year. We conducted mean comparisons by t tests and chi-square comparisons to examine differences in count of symptomatic UTIs. In addition, we performed a Poisson regression with count of symptomatic UTIs as the outcome to assess for potential factors that could be related to more frequent symptomatic UTIs including group assignment and demographic variables.

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Results 

The demographics of the sample are shown in table 1. The treatment group had significantly more subjects who were nonwhite and more subjects with paraplegia (compared with tetraplegia). No other significant differences between groups were found.

Twelve subjects (54%) in the hydrophilic catheter group and 14 subjects (61%) in the control group had at least 1 symptomatic UTI during the course of the 1-year study. On the basis of our definition of UTI, the mean total number of UTIs during the 1 year of study was 1.18 for the hydrophilic catheter group and 1.00 for the control group. There was no difference in the number of symptomatic UTIs in the group who used the hydrophilic catheter compared with the group who used the uncoated catheters. However, as can be seen in table 1, the mean number of UTIs that was associated with antibiotic treatment was significantly lower for the hydrophilic group than for the control group.

A Poisson regression was conducted to examine variables associated with higher numbers of UTIs including group (treatment vs control), sex (men vs women), level of injury (paraplegia vs tetraplegia), and years with injury (quartiles with range 6mo to 53y). Results suggested that women had more frequent UTIs when all other variables remained the same.

The most common UTI symptoms were the same in both groups, although the frequency differed somewhat. In the treatment group, the symptoms were in descending order: cloudy urine, incontinence, feeling tired, increased frequency, and foul-smelling urine. In the control group, the symptoms were in descending order: cloudy urine, foul-smelling urine, incontinence, feeling tired, and increased frequency.

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Discussion 

Our study demonstrates that hydrophilic catheter usage is associated with reduced numbers of treated UTIs as compared with standard nonhydrophilic catheters, but there was no difference in the number of subjects who had at least 1 UTI found across groups. However, being female was related to more frequent UTIs, regardless of the type of catheter they used. Although the criterion for entry into the study was having 2 or more UTIs in the past year, results of the current study showed that on average, both groups had approximately 1 UTI during the year of the study. This may be due to a variety of factors, such as improved technique from education and monitoring¹⁶; the use of a new catheter for every catheterization, which is not standard; or simply inaccurate self-report of UTIs for the period before enrollment.

The largest of previous studies, that by De Ridder et al,¹³ included only men who had been injured less than 6 months and had a very high dropout rate (53.7%), with only 57 participants remaining in the study at the end of 1 year. Restored urinary function and change to an indwelling catheter were given as the main reasons for the high withdrawal rate. In our study, women were included and subjects were community-dwelling persons with SCI who had been injured 6 months to more than 53 years previously. In addition, subjects in our study had fewer total UTIs, and no one changed to an indwelling catheter during the study period or recovered bladder function. Although it would have reduced the effect of prior modes of bladder drainage to enroll patients onto the study during hospitalization, knowing that the function of the neurogenic bladder in the patient with acute SCI evolves during the first year and patients also often change type of bladder drainage during the first year,¹⁷ we chose to study persons with chronic SCI and problems with recurrent UTIs.

Study Limitations 

Limitations of this study need to be considered when interpreting these results. On the basis of the sample size, we may be underpowered to detect differences between the 2 groups. Both the number of symptomatic UTIs was below that expected, and the sample size was smaller. The small number of women in our study is a limitation of the study, and it is possible that the finding that being a woman increased the risk of UTI regardless of type of catheter is not true. Interestingly, in a recent large study of 912 community-dwelling persons with SCI, half of whom were women, among IC users, women reported a significantly greater number of UTIs than men (P=.003).¹⁸ Another limitation of our study was the use of self-reported symptoms. We collected data regarding symptoms from the patient from a list of symptoms; thus, it is possible that the patient was more likely to report a symptom than not. The symptoms we collected, however, did not play a role in clinical decisions made by the subject's physician regarding the diagnosis or treatment of any UTI. We chose to examine episodes of treated UTIs because we did not want to interfere with usual clinical practice.

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Conclusions 

Although there was no difference in the number of symptomatic UTIs in the 2 groups, it appears that the mean number of UTIs treated with antibiotics was significantly smaller in the hydrophilic group. This finding merits further investigation. Women in this study were more likely to develop UTIs regardless of the catheter type, suggesting that the benefits of the lubrication may be more important in men.

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References 

1. National Spinal Cord Injury Statistical Center. Annual reports 9 and 10 for the model Spinal Cord Injury Care Systems. Birmingham: NSCISC; 1992;
   • View In Article
2. Charlifue SW, Weitzenkamp DA, Witeneck GG. Longitudinal outcomes in spinal cord injury: aging, secondary conditions, and well-being. Arch Phys Med Rehabil. 1999;80:1429–1434
   • View In Article
   • Abstract
   • Full-Text PDF (727 KB)
   • CrossRef
3. Esclarín de Ruz A, García Leoni E, Huerruzo Cabrera R. Epidemiology and risk factors for urinary tract infection in patients with spinal cord injury. J Urol. 2000;164:1285–1289
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (56 KB)
   • CrossRef
4. Cardenas DD, Hoffman JM, Krishblum S, McKinley W. Etiology and incidence of rehospitalization after traumatic spinal cord injury: a multicenter analysis. Arch Phys Med Rehabil. 2004;85:1757–1763
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (128 KB)
   • CrossRef
5. Vickrey BG, Shekelle P, Morton S, Clark K, Pathak M, Kamberg C. Prevention and management of urinary tract infections in paralyzed persons. Evid Rep Technol Assess (Summ). 1999;(6):1–3
   • View In Article
6. Larsen LD, Chamberlin DA, Khonsari F, Ahlering TE. Retrospective analysis of urologic complications in male patients with spinal cord injury managed with and without indwelling urinary catheters. Urology. 1997;50:418–422
   • View In Article
   • Abstract
   • Full-Text PDF (490 KB)
   • CrossRef
7. Consortium for Spinal Cord Medicine (Bladder management for adults with spinal cord injury: a clinical practice guideline for health care providers). Washington (DC): Paralyzed Veterans of America; 2006;
   • View In Article
8. Hedlund H, Hjelmås K, Jonsson O, Klarskov P, Talja M. Hydrophilic versus non-coated catheters for intermittent catheterization. Scand J Urol Nephrol. 2001;35:49–53
   • View In Article
   • MEDLINE
   • CrossRef
9. Waller L, Jonsson O, Norlén L, Sullivan L. Clean intermittent catheterization in spinal cord injury patients: long-term followup of a hydrophilic low friction technique. J Urol. 1995;153:345–348
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (477 KB)
   • CrossRef
10. Vaidyanathan S, Soni BM, Dundas S, Krishnan KR. Urethral cytology in spinal cord injury patients performing intermittent catheterisation. Paraplegia. 1994;32:493–500
    • View In Article
    • MEDLINE
    • CrossRef
11. Vapnek JM, Maynard FM, Kim J. A prospective randomized trial of the LoFric hydrophilic coated catheter versus conventional plastic catheter for clean intermittent catheterization. J Urol. 2003;169:994–998
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (1624 KB)
    • CrossRef
12. Sutherland RS, Kogan BA, Baskin LS, Mevorach RA. Clean intermittent catheterization in boys using the LoFric catheter. J Urol. 1996;156:2041–2043
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (340 KB)
    • CrossRef
13. De Ridder DJ, Everaert K, Fernánez LG, et al. Intermittent catheterisation with hydrophilic-coated catheters (SpeediCath) reduces the risk of clinical urinary tract infection in spinal cord injured patients: a prospective randomised parallel comparative trial. Eur Urol. 2005;48:991–995
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (148 KB)
    • CrossRef
14. Fader M, Moore KN, Cottenden AM, Pettersson L, Brooks R, Malone-Lee J. Coated catheters for intermittent catheterization: smooth or sticky?. BJU Int. 2001;88:373–377
    • View In Article
    • MEDLINE
    • CrossRef
15. American Spinal Injury Association. Reference manual of the international standards for neurological classification of spinal cord injury. Chicago: American Spinal Injury Association; 2003;
    • View In Article
16. Cardenas DD, Hoffman JM, Kelly E, Mayo ME. Impact of a urinary tract infection educational program in persons with spinal cord injury. J Spinal Cord Med. 2004;27:47–54
    • View In Article
    • MEDLINE
17. Cardenas DD, Mayo ME. Bacteriuria with fever after spinal cord injury. Arch Phys Med Rehabil. 1987;68(5 Pt 1):291–293
    • View In Article
    • MEDLINE
18. Woodbury MG, Hayes KC, Askes HK. Intermittent catheterization practices following spinal cord injury: a national survey. Can J Urol. 2008;15:4065–4071
    • View In Article

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