Impact of StatLock securing device on symptomatic catheter-related urinary tract infection: A prospective, randomized, multicenter clinical trial Rabih O. Darouiche, MD, a,b Lance Goetz, MD, c,d Teresa Kaldis, MD, b,e Colleen Cerra-Stewart, RN, a Atef AlSharif, MD, b and Michael Priebe, MD f Houston and Dallas, Texas; and Hines, Illinois Background: The objective of this study was to assess the impact of using the StatLock securing device on symptomatic catheterrelated urinary tract infection (UTI). Methods: In this prospective, randomized, multicenter clinical trial, adult patients with spinal cord injury or dysfunction because of multiple sclerosis were randomized to have their indwelling bladder catheters secured in place by using the StatLock device (experimental group) versus preexisting methods (control group that included tape, Velcro strap, CathSecure, or none). Patients were monitored for the development of symptomatic UTI within the subsequent period of 8 weeks. Results: Of a total of 127 enrolled patients, 118 (60 in the experimental group and 58 in the control group) were evaluable. The 2 groups of evaluable patients were comparable in terms of clinical characteristics and risk factors for infection. Symptomatic UTI was diagnosed in 8 of 60 (13.3%) patients in the experimental group versus 14 of 58 (24.1%) patients in the control group (P 5.16; RR 5 0.55, 95% confidence interval: 0.25-1.22). Conclusion: Although the trial size precluded the demonstration of statistically significant differences, the finding of a 45% reduction in the rate of symptomatic UTI in patients who received the StatLock securing device is clinically relevant and prompts further investigations. (Am J Infect Control 2006;34:555-60.) Most cases of health care-acquired urinary tract infection (UTI) are catheter related. 1 Although the likelihood of developing bloodstream infection because of indwelling bladder catheters is generally low (,1%), the tremendous number of inserted bladder catheters (30 million inserted each year in the United States) 2 makes catheter-related UTI the second most common cause of nosocomial bloodstream infection (after vascular catheters). 3,4 The problem of UTI is particularly From the Michael E. Debakey Veterans Affairs Medical Center, a Houston, TX; Baylor College of Medicine, b Houston, TX; Veterans Affairs North Texas Healthcare System, c Dallas, TX; University of Texas-Southwestern Medical Center at Dallas, d Dallas, TX; The Institute for Rehabilitation and Research, e Houston, TX; and Hines Veterans Affairs Medical Center, f Hines, IL. Address correspondence to Rabih O. Darouiche, MD, Center for Prostheses Infection, Baylor College of Medicine, 1333 Moursund Avenue, Suite A221, Houston, TX 77030. E-mail: rdarouiche@aol.com. Presented in part at the 15th Annual Meeting of the Society for Healthcare Epidemiology of America, Los Angeles, CA, 2005; Abstract No. 163. Supported by funds from the Department of Veterans Affairs, Washington, DC, and by a grant from Venetec International, San Diego, CA. The funding institutions played no role in the conduct of the study and did not contribute to the decision to submit the manuscript for publication. 0196-6553/$32.00 Copyright ª 2006 by the Association for Professionals in Infection Control and Epidemiology, Inc. doi:10.1016/j.ajic.2006.03.010 prominent in patients with chronic indwelling bladder infections, including a significant portion of the US population of 247,000 persons with spinal cord injury (SCI). 5 Although long-term use of systemic antibiotic prophylaxis in patients with either acute 6 or chronic 7 SCI may afford some protection against UTI because of organisms susceptible to the administered prophylactic agents, this result is achieved at the expense of a surge in the rate of infection because of resistant pathogens and adverse drug reactions. Moreover, neither in able-bodied persons nor in patients with SCI have local antimicrobial-utilizing approaches including daily care of the urethral meatus, 8-10 disinfection of the collection bag, 11,12 and irrigation of the catheter and bladder 13,14 been demonstrated to prevent adequately the catheter-related UTI. The limited success of such antimicrobial-utilizing approaches prompted our interest in exploring the potential preventive efficacy of nonantimicrobial measures. 15 A prospective, randomized clinical trial had demonstrated that use of the StatLock device (Venetec International, San Diego, CA) for securing central venous catheters significantly reduces the incidence of catheter-related bloodstream infection, as compared with suture placement. 16 The antiinfective benefit of using the StatLock device to secure vascular catheters probably derives from both the elimination of skin sutures to which bacteria can adhere and minimization of 555
556 Vol. 34 No. 9 Darouiche et al the to-and-fro pistoning of the catheter that would favor invasion of the subcutaneous tract by skin organisms. 17 When utilized to secure a bladder catheter in place, the StatLock device also serves to limit the toand-fro movement of the catheter that would traumatize tissues and encourage their invasion by microbial pathogens. The potential antiinfective impact of using the StatLock device to secure urinary catheters has not been evaluated in a prospective randomized fashion. The main objective of this prospective, randomized clinical trial was to assess the impact of using the StatLock device on the rate of symptomatic UTI associated with indwelling bladder catheters. METHODS Study design This prospective, randomized, multicenter clinical trial was approved by the institutional review boards of all 4 participating, tertiary care medical centers. Adult patients with SCI who were diagnosed with neurogenic bladder and required a long-term indwelling transurethral or suprapubic bladder catheter were eligible for enrollment in the study. After obtaining an informed consent from the patients or their legal guardians, enrolled patients were randomized (using a separate randomization scheme at each participating site), in a 1:1 ratio, to 1 of 2 groups: (1) the experimental group had their indwelling bladder catheters secured in place by using the StatLock device (Venetec International, San Diego, CA), and (2) the control group continued to utilize their prestudy traditional methods that included tape, Velcro strap, Cath-Secure (MC Johnson Co, Inc, Naples, FL), or none. Bladder catheters were changed at enrollment and every 4 weeks (as per preexisting practices of the participating hospitals) or earlier in case of catheter blockage. Both the StatLock and the control securing devices were changed every week (according to preexisting practices of the participating hospitals). Nurses cleansed the catheterized area with soap and water on a daily basis. Monitoring and microbiologic evaluation Patients were monitored for the development of symptomatic UTI within the period of 8 weeks after enrollment in the study. In patients who were suspected to have UTI, urine samples were obtained for microscopic analysis and routine bacterial cultures. Standard microbiologic methods were used to identify and quantify isolated organisms. Urine samples were generally collected by aseptic needle puncture from the sampling port to avoid contamination of the drainage system. Disconnection of the catheter-drainage tubing junction to obtain a urine sample was permitted only at the time of catheter exchange. Collection of urine samples from the drainage bag was not allowed. To ensure that diagnosed episodes of symptomatic UTI are catheter related, bladder catheters were removed, and the 4-cm intraurethral segment proximal to the balloon was cultured by using the same roll-plate technique that is commonly utilized to culture vascular catheters. 18 Standard microbiologic methods were used to identify and determine the colony counts of organisms isolated from cultured catheters. Outcomes Using an established definition of symptomatic UTI in patients with SCI, 19-21 the primary outcome of symptomatic UTI was diagnosed by the presence of significant bacteriuria ($10 4 cfu/ml) and pyuria (.10 WBC/hpf) plus 1 or more of the following clinical signs and symptoms for which no other etiology could be identified: fever (oral temperature.100 F), suprapubic or flank discomfort, bladder spasm, increased spasticity, and worsening dysreflexia (usually manifested by increase in blood pressure, headache, sweating above the SCI lesion, and flushing below the SCI lesion). Symptomatic UTI was diagnosed by evaluators who were intentionally kept unaware of the type of catheter-securing device used in individual patients. To help ensure that the examined outcome of symptomatic UTI was truly associated with the study-assigned type of catheter-securing method, this study was designed to consider only patients who are monitored for.10 days after enrollment as evaluable for analysis. Patients who developed symptomatic UTI were treated with antibiotics guided by antimicrobial susceptibilities. We also evaluated secondary outcomes including dislodgement of the bladder catheter and new visually observed areas of erosion of the urethral meatus. Sample size We hypothesized that the incidence of symptomatic UTI among study participants would be reduced by half in patients whose bladder catheters are secured with the StatLock device (25%) as compared with patients who rely on traditional securement measures (50%). Randomizing approximately 65 patients to each study group would have allowed us to detect with 80% power a significant difference in the rates of symptomatic UTI at a 5% 2-tailed significance level. Statistical analysis The clinical characteristics and risk factors for symptomatic UTI in the 2 study groups were compared by using the Fisher exact or x 2 test for categorical
Darouiche et al November 2006 557 Table 1. Clinical characteristics and risk factors for infection Characteristics and risk factors Experimental group (n 5 60) variables and the Student t test for continuous variables. A 2-tailed Fisher exact test was used to compare the occurrence of outcomes in the experimental versus control group. A P value,.05 indicated statistical significance. RESULTS Patients and clinical characteristics Control group (n 5 58) Age, yr Mean 55 56 Median 53 55 Range 20-81 24-84 Male sex, n (%) 53 (88) 51(88) Type of spinal cord disease, n (%) Cervical injury 29 (48) 29 (50) Thoracolumbar injury 24 (40) 26 (45) Multiple sclerosis 7 (12) 3 (5) Type of bladder catheter, n (%) Transurethral 40 (67) 41 (71) Suprapubic 20 (33) 17 (29) UTI during past 38 (63) 42 (72) year, n (%) Duration of catheterization, day Mean 50 49 Median 56 56 Range 14-56 11-56 Catheter blockage 9 (15) 6 (10) during study, n (%) Antibiotic use during study, day Mean 13 15 Median 11 13 Range 0-56 0-56 Of 127 enrolled patients, 9 were not followed for.10 days and, therefore, were excluded from analysis. The 9 excluded patients included 5 in the experimental group (2 voluntarily withdrew from the study and 3 developed UTI #10 days after enrollment) and 4 in the control group (1 withdrew from the study and 3 developed UTI #10 days after enrollment). A total of 118 patients (60 in the experimental group and 58 in the control group) were evaluable. The 2 groups of evaluable patients had comparable clinical characteristics and risk factors for infection, including age, gender, type of spinal cord disease (cervical injury, thoracolumbar injury, or multiple sclerosis), type of indwelling bladder catheter (transurethral or suprapubic), history of UTI during the year prior to study enrollment, Table 2. Outcomes of study Outcome duration of catheterization during the study, catheter blockage during the study, and length of antibiotic therapy during the study (Table 1). UTI As Table 2 shows, 8 of 60 (13.3%) patients in the experimental group versus 14 of 58 (24.1%) patients in the control group developed symptomatic UTI (P 5.16; RR 5 0.55, 95% CI: 0.25-1.22). Because the duration of catheterization was similar between the 2 study groups (mean of 50 days in the experimental group and 49 days in the control group), there was also a statistically insignificant trend (P 5.16) for lower incidence of symptomatic UTI per 1000 device-days in the experimental group (2.7/1000 device-days) than in the control group (4.9/1000 device-days). The statistically insignificant trend for lower incidence of symptomatic UTI in association with the use of the StatLock device versus control measures existed regardless of whether patients used a transurethral catheter (7/40, 18.5% vs 12/41, 29%, respectively) or a suprapubic catheter (1/20, 5% vs 2/17, 11.8%, respectively). When including only patients in the control group, those whose bladder catheters were secured by using the different types of traditional securing approaches (ie, tape, Velcro strap, Cath-Secure, or none) had similar rates of symptomatic UTI. Microbiology of UTI Experimental group (n 5 60) Control group (n 5 58) Symptomatic UTI, n (%) 8 (13.3) 14 (24.1) Symptomatic UTI, 2.7 4.9 n/1000 device-days Secondary outcomes, n (%) Catheter dislodgement 1 (1.7) 3 (5.2) New meatal erosion 2 (3.4) 3 (5.2) Among the total of 22 episodes of symptomatic UTI, 9 (41%) were caused by a single organism, and 14 (59%) were polymicrobial (2 or 3 organisms). Gram-negative bacilli caused 7 (2 by Escherichia coli; 2byProteus mirabilis; and1byeachofklebsiella pneumoniae, Providentia stuartii, andserratia marcescens) ofthe9unimicrobial episodes of symptomatic UTI, whereas Entercoccus faecalis and Candida albicans caused 1 episode each. In 4 of 14 patients with polymicrobial bouts of symptomatic UTI, both Candida and bacterial species grew from the urine cultures. Overall, the 3 most common isolated organisms were Candida (in 5 patients), E coli(in 4 patients), and K pneumoniae (in 4 patients). There were no differences between patients who received the StatLock device versus control securing
558 Vol. 34 No. 9 Darouiche et al measures with respect to the type or concentration of organisms in urine cultures. Bladder catheters were cultured upon diagnosing symptomatic UTI in 18 patients (6 in the experimental group and 12 in the control group); the bladder catheters in the remaining 4 patients were not available for culture. In all 18 patients, catheter cultures yielded the same organism(s) that also grew from urine cultures, and, in some patients, catheter cultures yielded additional organism(s). Secondary outcomes There were no statistically significant differences in the rates of catheter dislodgement and urethral meatal erosion in patients whose catheters were secured in place by using the Statlock device versus other measures (Table 2). DISCUSSION Prevention of UTI, the most common health careacquired infection, can be difficult to achieve, particularly in patients with long-term indwelling bladder catheters. 15,22 The results of this clinical trial indicate that the use of the StatLock securing device was associated with a 45% reduction in the rate of symptomatic UTI in patients with a catheter-dependent neurogenic bladder. Although this observed level of protection against UTI that was afforded by the use of the StatLock securing device was just below the 50% level of protection that we predicted when estimating the study size, the overall rates of symptomatic UTI that were actually experienced by both study groups were almost twice lower than the anticipated rates. This helps explain why this clinical trial ended with not having sufficient power to demonstrate significant differences in the rate of symptomatic UTI in the experimental versus control group. Although the difference was not statistically significant, this level of reduction in the rate of symptomatic UTI is clinically relevant, particularly because no antimicrobial-utilizing approach has been shown in a prospective randomized clinical trial to be associated with a higher level of protection against catheter-related UTI. 23 A sufficiently powered, larger size, clinical trial might demonstrate significant protection against symptomatic UTI and, possibly, show a decrease in the rate of catheter dislodgment or meatal erosion when using the StatLock securing device. The introduction of the closed urinary drainage system 4 decades ago conferred the highest level of protection against catheter-related UTI and abolished the use of open catheter drainage. 24 Unfortunately, potentially preventive measures that have been explored since were less successful. Although some antimicrobialcoated vascular catheters have been demonstrated in prospective, randomized clinical trials to protect significantly against catheter-related bloodstream infection, 25,26 antimicrobial-coated urinary catheters have generally not been found to be as protective. The lesser degree of protection afforded by antimicrobial-coated urinary versus vascular catheters can be attributed, at least in part, to differences in the pathogenesis of infections associated with the 2 types of catheters. 23 For instance, the very high bacterial concentration in urine (often.10 5 cfu/ml) may overwhelm the antimicrobial activity of coated bladder catheters, 27 whereas similarly coated vascular catheters that are exposed to much lower number of bacteria residing in the skin adjacent to the insertion site may be very protective. 28 A major limitation in assessing the potential benefit of antimicrobial-coated urinary catheters is that almost all clinical trials have utilized bacteriuria (which most often is asymptomatic but is mislabeled as UTI) rather than symptomatic UTI (ie, symptomatic infection characterized by bacteriuria, pyuria, and clinical signs and symptoms of infection) as the main outcome. 27,29-31 Although bacteriuria can be a prelude to symptomatic UTI, a reduction in bacteriuria is not necessarily indicative of protection against symptomatic UTI. The variable and often suboptimal design of clinical trials of antimicrobial-coated urinary catheters pose another limitation in assessing the true clinical benefit of such technologic advances. For instance, most reports in peer-reviewed journals of bladder catheters coated with silver alloy and hydrogel were either prospective crossover studies 32 or prospective surveillance of outcomes associated with coated catheters in comparison with historical or baseline outcomes associated with uncoated catheters, 33-35 and only 1 clinical trial was prospective randomized. 30 Not unexpectedly, some of these clinical trials demonstrated significant differences in outcome when using bladder catheters coated with silver alloy and hydrogel, 32,33 whereas others did not. 30,34,35 Although evaluator-blinded, this clinical trial could not be conducted in a double-blind fashion because patients could easily visualize the assigned cathetersecuring device. Because an equivalent proportion of patients in the 2 groups were judged during the study period to have symptomatic episodes that were attributed to etiologies other than UTI, it is unlikely that biased observations accounted for lower rates of symptomatic UTI in the experimental versus control group. There were 2 intriguing microbiologic findings in our study: more than half of the bouts of symptomatic UTI in this study were polymicrobial, and a Candida species was cultured from the urine of more than one fifth of infected patients. These observations support the perspective that the likelihood of potentially
Darouiche et al November 2006 559 preventive approaches, both antimicrobial and nonantimicrobial, to protect against symptomatic UTI depends, at least in part, on their abilities to resist infection by a wide variety of organisms, including Candida. We found no differences between the experimental and control groups of patients with respect to the microbiology of symptomatic UTI, the concentrations of organisms in urine cultures, and the concomitant presence of organisms in urine and catheter cultures findings compatible with the nonantimicrobial nature of the StatLock securing device. By providing a better securement for the bladder catheter, the StatLock device could protect against symptomatic UTI by reducing mucosal irritation and perhaps minimizing the disruption of the biofilm surrounding the catheter. 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