Inappropriate use of urinary catheters: A prospective observational study

Transcription

1 Inappropriate use of urinary catheters: A prospective observational study Manish M. Tiwari, MD, PhD, MPH, a Mary E. Charlton, PhD, a James R. Anderson, PhD, a Elizabeth D. Hermsen, PharmD, b and Mark E. Rupp, MD a Omaha, Nebraska Background: Despite the well-recognized role of urinary catheters in nosocomial urinary tract infections, data on risk factors associated with inappropriate urinary catheter use are scarce. Methods: A prospective review of electronic medical records of 436 patients admitted to an adult medical-surgical unit between October and December 2007 was performed to examine the appropriateness of urinary Results: The use of 157 urinary catheters in 144 patients was observed. A total of 557 urinary catheter-days were recorded in these patients, of which 175 (31.4%) were found to be inappropriate based on the study criteria. The total number of catheters used and the total duration of catheterization were risk factors for inappropriate urinary catheter use (P,.05). Inappropriate catheter use was not associated with such adverse events as mortality, readmission, intensive care unit admission, catheter complications, or urine culture rates, but was associated with a trend toward longer duration of hospitalization. Conclusions: Significant rates of inappropriate urinary catheter use and a trend toward longer duration of hospitalization with inappropriate catheter use were observed. These findings underscore the importance of establishing guidelines and effective policy implementation for the appropriate use of urinary catheters in hospitalized patients. Key Words: Urinary tract infection; catheter-associated urinary tract infection; inappropriate use; risk factor. Copyright ª 2011 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. (Am J Infect Control 2011;n:1-5.) Urinary catheters are indispensable tools and among the most common medical devices used in patient management. It is estimated that approximately 25% of hospitalized patients have an indwelling urinary catheter in place at some time during the course of their hospitalization. 1 The use of indwelling urinary catheters in hospitalized patients is now well recognized as a significant risk factor in the development of nosocomial urinary tract infections. 2 Catheterassociated urinary tract infections (CAUTIs) account for nearly 40% of all nosocomial infections. 3 Among catheterized patients, the incidence of CAUTIs is ;5% per day, resulting in an estimated 800,000 infections per year. 4,5 Several studies have associated CAUTIs with longer duration of hospitalization and excess costs. 6-9 Previous observational studies have identified various risk factors for CAUTI, including age, sex, duration of catheterization, and presence of comorbid From the University of Nebraska Medical Center, a and Nebraska Medical Center, Omaha, NE. b Address correspondence to Mark E. Rupp, MD, Infectious Diseases, Nebraska Medical Center, Omaha, NE merupp@unmc.edu. Conflict of interest: None to report /$36.00 Copyright ª 2011 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. doi: /j.ajic conditions. 10,11 Recently, it has become increasingly clear that the inappropriate use of urinary catheters during hospitalization accounts for a substantial number of CAUTIs and a significant percentage of preventable CAUTI-associated morbidity. 10,12 Despite growing evidence of the role of inappropriate urinary catheter use in development of CAUTI, data on risk factors associated with inappropriate urinary catheter use, particularly in non intensive care unit (ICU) settings, are relatively scarce. The objectives of this prospective study were to examine the appropriateness of urinary catheter use in a non-icu setting using specific predetermined clinical criteria, to examine risk factors associated with inappropriate urinary catheter use, and to assess clinical outcomes associated with inappropriate METHODS Study setting and design This Institutional Review Board approved prospective study was conducted between October and December of 2007 in an adult general medical-surgical unit at the Nebraska Medical Center. All patients admitted to the unit during the study period were included in the study. Before study initiation, the accuracy of electronic data was validated by comparing electronic and paper medical records. This process was repeated periodically throughout the study to ensure accuracy of records. In addition, several point prevalence 1

2 2 Tiwari et al. American Journal of Infection Control n 2011 surveys had been performed previously by Department of Healthcare Epidemiology personnel to ensure the accuracy of electronic data regarding the presence of a urinary catheter (unpublished data). Data collection Data were extracted on a daily basis from patients with and without urinary catheters by an independent observer not associated with day-to-day patient care. Data extracted included demographic information, such as age and sex, length of hospital stay, medical history and diagnosis, and outcome measures such as mortality, readmission within 30 days, and ICU admission. In addition, data on urinary catheter use were recorded, including type of catheter used, duration of catheter use, device-related complications, and urine culture results. Ward personnel were not aware of details of the study during the course of the study. Criteria for appropriate urinary catheter use Criteria used to classify urinary catheter devices as appropriate were developed before the start of the study from previously accepted indications. 10,13,14 In brief, the use of a urinary catheter was considered appropriate for any of the following indications: urinary retention, urine output monitoring, medication instillation, urinary tract obstruction, neurogenic bladder dysfunction, immediate postoperative management in surgical patients, decubitus ulcer or other wounds with a need for urinary diversion, or comfort care in the terminally ill. The presence of urinary incontinence with one of these appropriate indications was classified as an appropriate However, the use of a urinary catheter for urinary incontinence alone was classified as inappropriate Scores from the activity and mobility sections of the Braden pressure ulcer risk assessment scale were used to partially determine the appropriateness of urinary catheter use in postoperative patients; specifically, an activity and mobility score of,4 on the Braden risk assessment scale was considered to support urinary Braden scores were calculated daily by nursing staff as part of routine pressure ulcer prevention practice. Determination of appropriateness of urinary catheter use Prospective follow-up of patients with a urinary catheter in place was done daily to determine appropriateness of use. Each day withaurinarycatheter in place was considered 1 catheter-day. For each patient, the total number of urinary catheters used, total catheter-days, appropriate catheter-days, and inappropriate catheter-days were calculated at the end of hospitalization. Statistical analysis Statistical analyses were performed using SAS software (SAS Institute, Cary, NC). Analyzed data for categorical variables are presented here as frequency distribution percentage and continuous variables as mean 6 SD. A P value,.05 was considered significant. Univariate logistic regression analysis was performed to compare patients with and without a urinary catheter to identify risk factors associated with urinary catheter use and appropriateness of use. The presence of a urinary catheter and appropriateness of urinary catheter use were modeled as functions of predictors or risk factors. To examine the outcome measures associated with urinary catheter use and inappropriate use, an additional logistic regression analysis was performed. Unadjusted odds ratios (ORs) and 95% confidence intervals (CIs) are presented for associations between the variables. For comparison of duration of catheterization (continuous variable) as an outcome measure of inappropriate catheter use, a 2-tailed t test was performed. Adjusted ORs with 95% CIs were calculated using stepwise logistic regression analysis to model the effects of multiple variables on outcomes of interest. RESULTS Patient characteristics and urinary catheter use Tables 1 and 2 summarize patient and catheter characteristics, respectively. A total of 436 patients were observed, 252 females (57.8%), with a mean age of A total of 2,909 days of hospitalization were recorded during the study period, with a mean duration of hospitalization of 6.7 days. A total of 144 patients (33.0%) had a urinary catheter in place at some point during hospitalization; 157 urinary catheters were used in these patients, for a mean of urinary catheters per patient. A total of 557 catheter-days were recorded, with a mean duration of catheterization of catheter-days per catheterized patient. The most common indication for urinary catheter use was surgery or postoperative management. A total of 111 patients (77.6% of patients with a urinary catheter) had a urinary catheter in place for surgery or postoperative management. No indication for urinary catheterization was found in 8 patients (5.6%) with a urinary catheter. Based on our criteria, 175 (31.4%) of urinary catheter-days were deemed to be inappropriate. Approximately 40% (n 5 58) of patients with a urinary catheter experienced at least 1 day of inappropriate catheterization.

3 Vol. n No. n Table 1. Urinary catheter use: Patient characteristics Variable Total n Mean 6 SD Number of patients Age, years Female sex 252 (57.8%) Length of stay, days 2, Patients with urinary catheter Total catheters Total catheter-days Appropriate catheter-days Inappropriate catheter-days Table 2. Indications of urinary catheter use Catheter indication* Patients with urinary catheter, n (%) No indication 8 (5.6%) Urinary retention 2 (1.4%) Monitoring urine output 10 (7.0%) Urinary tract obstruction 2 (1.4%) Neurogenic bladder dysfunction 4 (2.8%) Surgery or postoperative management 111 (77.6%) Decubitus ulcer or need for diversion 5 (3.5%) Comfort care in terminally ill 3 (2.1%) *Multiple indications present in some patients. Predictors and outcomes of urinary catheter use Univariate logistic regression analysis performed to identify the factors associated with urinary catheter use found that only patient age was significantly associated with Patients with a urinary catheter were significantly older than those without a catheter. After controlling for patient sex, a significant association with age persisted when multivariate logistic regression analysis was performed (Table 3). Logistic regression analysis of the relationship between urinary catheter use and adverse events showed no significant association between the catheter use and mortality, readmission within 30 days, or ICU admission. However, patients with a urinary catheter had significantly higher urine culture rates compared with uncatheterized patients (Table 3). Patients with a urinary catheter had a significantly longer duration of hospitalization ( days vs days; P,.05). These significant associations remained when potential confounding factors, such as age and sex, were controlled for in a multivariate logistic regression model. Predictors and outcomes of inappropriate urinary catheter use Associated factors and outcomes of inappropriate urinary catheter use are summarized in Table 4. Table 3. Logistic regression models of the relationships among patient characteristics, urinary catheter use, and adverse events Variable Logistic regression analysis found significant associations between inappropriate urinary catheter use an increased number of urinary catheters used (unadjusted OR, 4.426; 95% CI, ; P,.05) and increased duration of urinary catheterization (unadjusted OR, 1.168; 95% CI, ; P,.05). After controlling for potential confounding factors, only increased duration of catheterization was found to be significantly associated with inappropriate urinary Logistic regression models of the relationship between inappropriate urinary catheter use and adverse events indicated that none of the outcome measures, including mortality, readmission, ICU admission, catheter complications, or urine culture rate, was significantly associated with inappropriate use. Inappropriate urinary catheter use was associated with a trend toward a longer duration of hospitalization ( days for appropriate use vs days for inappropriate use; P 5.07). DISCUSSION Unadjusted OR (95% CI) Adjusted OR (95% CI)* Patient characteristics versus urinary catheter use Sex, female versus male ( ) 0.98 ( ) Age, years ( ) y ( ) y Urinary catheter use versus adverse events Mortality ( ) ( ) Readmission ( ) ( ) ICU admission ( ) ( ) Urine culture ( ) y ( ) y *Multivariate logistic regression model includes age and sex. y Significant at P,.05. Tiwari et al. 3 Although emerging evidence indicates that inappropriate use of urinary catheters is associated with CAUTI-related morbidity, 10,13 data on risk factors associated with inappropriate urinary catheter use in non-icu settings are sparse. One-third of the patients enrolled in this study had a urinary catheter in place at some point during hospitalization, and the patients with a urinary catheter were significantly older than those without a catheter. Age has been identified as a significant risk factor for urinary 12,15 No significant association between sex and urinary catheterization was noted. After controlling for sex, older age remained significantly associated with urinary Of the outcomes measures examined in this study, only increased urine culture rate was significantly

4 4 Tiwari et al. American Journal of Infection Control n 2011 Table 4. Logistic regression models of the relationships among patient characteristics, inappropriate urinary catheter use, and adverse events Variable Unadjusted OR (95% CI) Adjusted OR (95% CI)* Patient characteristics versus inappropriate catheter use Sex, female versus male ( ) ( ) Age, years ( ) ( ) Total catheters, multiple versus single ( ) y ( ) Duration of catheterization z ( ) y ( ) y Inappropriate catheter use versus adverse events Mortality ( ) ( ) Readmission ( ) ( ) ICU admission ( ) ( ) Catheter complications ( ) ( ) Urine culture ( ) ( ) *Multivariate logistic regression model includes sex, age, total catheters, and duration of catheterization. y Significant at P,.05. z Duration of catheterization, days. associated with the use of urinary catheters. Other outcome measures mortality, ICU admission, and readmission were not associated with urinary catheter use. This is not surprising given that the study was carried out in a non-icu medical-surgical unit in which patient illness severity might have differed greatly from that in an ICU setting. This finding is consistent with a recent meta-analysis examining the relationships between outcome measures and urinary catheter use in critically ill patients. The study found no relationship between increased mortality and hospital length of stay after statistical adjustment in patients with urinary 16 According to the predetermined study criteria for appropriate urinary catheter use, the most common appropriate indication for catheter use was for surgery or postoperative management, accounting for nearly 78% of appropriate use. This finding was expected, given that the study was performed in a hospital general medical-surgical unit. Approximately 40% of patients with a urinary catheter experienced at least 1 inappropriate catheter-day, and approximately 31% of the urinary catheter-days were deemed inappropriate. These results are consistent with previous studies reporting inappropriate use in 30%-40% of catheterized patients. 10,12,17 Logistic regression models indicate that inappropriate use was more likely in patients with multiple urinary catheters during hospitalization. In addition, inappropriate use was strongly associated with increased duration of catheterization. Although the present study did not document the exact excessive duration of catheterization, previous studies have shown that catheterization beyond 3-5 days is a strong risk factor for inappropriate urinary 12,13 The present study also found an association between older patient age and increased urinary catheter use; however, age was not a predictor of inappropriate This is in contrast to a previous study reporting a significantly association between age and inappropriate urinary 12,13 Surprisingly, our findings do not demonstrate a significant association with such outcome measures as mortality, readmission, ICU admission, urinary catheter complications, and urinary culture rate. We found a marginal, but not statistically significant, association between inappropriate use and longer duration of hospitalization (P 5.07), consistent with a previous study. 10 The present study has several limitations. First, the study was conducted in a single medical-surgical unit at a single institution, and thus the findings might have limited generalizability. Second, although our results do not indicate an increased risk of adverse outcomes with inappropriate urinary catheter use, because of the sample size an association cannot be ruled out. In addition, other potential variables for inappropriate catheterization, such as a physician s preference and practice for catheterization, were not examined. Another significant limitation is the failure to incorporate severity of patient illness or medical diagnosis in the analysis. Finally, because it was assumed that the initial urinary catheterization was for an appropriate indication, some misclassification bias due to study design cannot be ruled out. This study is noteworthy for several reasons. Appropriateness of catheter use was prospectively evaluated on a daily basis. In contrast, most previous studies on the topic examined inappropriate catheter use only at the time of insertion based on the indication for insertion. 10,12,13,17 In addition, our findings confirm that urinary catheters are frequently used outside of ICU settings (approximately one-third of the patients on our general medical surgical ward), and that inappropriate urinary catheter use is common (;40% of catheterized patients experience at least 1 day of

5 Vol. n No. n unnecessary catheterization, and 31% of catheter days are inappropriate). The criteria for appropriate urinary catheter can be tracked electronically, followed serially, and potentially used for interventions to prevent unnecessary urinary Risk factors for inappropriate urinary catheter use and outcomes associated with inappropriate use were identified. These new findings might be used to identify patients at high risk for unnecessary urinary catheterization and target patient factors associated with inappropriate urinary Recently, such interventions as physician reminders and stop orders based on criteria for appropriate urinary catheter use, staff education and use of an indication sheet, and nurse-generated daily reminders to stop catheter use have been shown to prevent inappropriate urinary This study highlights the use of electronic charting to identify inappropriate urinary catheter use, which may be helpful in developing electronic alerts to limit unnecessary In conclusion, our findings demonstrate the frequent inappropriate use of urinary catheters in a non-icu setting, and suggest the potential usefulness of an electronic system to identify inappropriate urinary They also identify increased catheter use and duration of catheterization as risk factors for inappropriate urinary Patients with inappropriate catheter use showed a trend toward longer duration of hospitalization. These findings are crucial for the next logical step, the construction and deployment of electronic alerts to notify clinicians of patients experiencing inappropriate urinary This is critically important as preventing catheterization and limiting the duration of catheterization appears to be the single best approach to CAUTI prevention. References 1. Haley RW, Hooton TM, Culver DH, Stanley RC, Emori TG, Hardison CD, et al. Nosocomial infections in US hospitals, : estimated frequency by selected characteristics of patients. Am J Med 1981;70: Krieger JN, Kaiser DL, Wenzel RP. Urinary tract etiology of bloodstream infections in hospitalized patients. J Infect Dis 1983;148: Tiwari et al Haley RW, Culver DH, White JW, Morgan WM, Emori TG. The nationwide nosocomial infection rate: a new need for vital statistics. Am J Epidemiol 1985;121: Maki DG, Tambyah PA. Engineering out the risk for infection with urinary catheters. Emerg Infect Dis 2001;7: Warren JW. Catheter-associated urinary tract infections. Infect Dis Clin North Am 1997;11: Givens CD, Wenzel RP. Catheter-associated urinary tract infections in surgical patients: a controlled study on the excess morbidity and costs. J Urol 1980;124: Green MS, Rubinstein E, Amit P. Estimating the effects of nosocomial infections on the length of hospitalization. J Infect Dis 1982;145: Platt R, Polk BF, Murdock B, Rosner B. Mortality associated with nosocomial urinary tract infection. N Engl J Med 1982;307: Saint S. Clinical and economic consequences of nosocomial catheterrelated bacteriuria. Am J Infect Control 2000;28: Apisarnthanarak A, Rutjanawech S, Wichansawakun S, Ratanabunjerdkul H, Patthranitima P, Thongphubeth K, et al. Initial inappropriate urinary catheters use in a tertiary care center: incidence, risk factors, and outcomes. Am J Infect Control 2007;35: Wald HL, Ma A, Bratzler DW, Kramer AM. Indwelling urinary catheter use in the postoperative period: analysis of the National Surgical Infection Prevention Project data. Arch Surg 2008;143: Raffaele G, Bianco A, Aiello M, Pavia M. Appropriateness of use of indwelling urinary tract catheters in hospitalized patients in Italy. Infect Control Hosp Epidemiol 2008;29: Gokula RR, Hickner JA, Smith MA. Inappropriate use of urinary catheters in elderly patients at a midwestern community teaching hospital. Am J Infect Control 2004;32: Saint S, Lipsky BA. Preventing catheter-related bacteriuria: should we? Can we? How? Arch Intern Med 1999;159: Rogers MA, Fries BE, Kaufman SR, Mody L, McMahon LF Jr, Saint S. Mobility and other predictors of hospitalization for urinary tract infection: a retrospective cohort study. BMC Geriatr 2008;8: Chant C, Smith OM, Marshall JC, Friedrich JO. Relationship of catheter-associated urinary tract infection to mortality and length of stay in critically ill patients: a systematic review and meta-analysis of observational studies. Crit Care Med 2011;39: Munasinghe RL, Yazdani H, Siddique M, Hafeez W. Appropriateness of use of indwelling urinary catheters in patients admitted to the medical service. Infect Control Hosp Epidemiol 2001;22: Apisarnthanarak A, Thongphubeth K, Sirinvaravong S, Kitkangvan D, Yuekyen C, Warachan B, et al. Effectiveness of multifaceted hospitalwide quality improvement programs featuring an intervention to remove unnecessary urinary catheters at a tertiary care center in Thailand. Infect Control Hosp Epidemiol 2007;28: Gokula RM, Smith MA, Hickner J. Emergency room staff education and use of a urinary catheter indication sheet improves appropriate use of Foley catheters. Am J Infect Control 2007;35: Loeb M, Hunt D, O Halloran K, Carusone SC, Dafoe N, Walter SD. Stop orders to reduce inappropriate urinary catheterization in hospitalized patients: a randomized controlled trial. J Gen Intern Med 2008; 23: