Persistence of bacteriuria following gynaecological surgery: a trial of methenamine hippurate

Management of recurrent urinary tract infections in women

Urinary tract infections are highly prevalent and result in significant patient morbidity as well as large financial costs to healthcare systems. Recurrent urinary tract infections can be challenging for many healthcare professionals, and the repeated use of antibiotics in this patient cohort inevitably contributes to the growing issue of antimicrobial resistance and superbugs. It is essential that these patients are appropriately diagnosed and managed to ensure rapid resolution of symptoms and the prevention of chronic or recurrent urinary tract infections. There are several antibiotic-based options available for the prophylaxis of recurrent urinary tract infections however, in the current era of rising antimicrobial resistance, an awareness of antibiotic stewardship and the use of non-antibiotic alternatives for the treatment and prevention of urinary tract infections is of critical importance. We present a case-based multidisciplinary team discussion to highlight how women with recurrent urinary tract infections should be managed, encouraging the use of non-antibiotic prophylactic measures when suitable.

Level of evidence:

Level 5

Nonantibiotic prevention and management of recurrent urinary tract infection

Urinary tract infections (UTIs) are highly prevalent, lead to considerable patient morbidity, incur large financial costs to health-care systems and are one of the most common reasons for antibiotic use worldwide. The growing problem of antimicrobial resistance means that the search for nonantibiotic alternatives for the treatment and prevention of UTI is of critical importance. Potential nonantibiotic measures and treatments for UTIs include behavioural changes, dietary supplementation (such as Chinese herbal medicines and cranberry products), NSAIDs, probiotics, D-mannose, methenamine hippurate, estrogens, intravesical glycosaminoglycans, immunostimulants, vaccines and inoculation with less-pathogenic bacteria. Some of the results of trials of these approaches are promising; however, high-level evidence is required before firm recommendations for their use can be made. A combination of these agents might provide the optimal treatment to reduce recurrent UTI, and trials in specific population groups are required.

Methenamine hippurate for preventing urinary tract infections

BACKGROUND

Methenamine salts are often used as an alternative to antibiotics for the prevention of urinary tract infection (UTI). This review was first published in Issue 1, 2002 and updated in Issue 4, 2007.

OBJECTIVES

To assess the benefits and harms of methenamine hippurate in preventing UTI.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library), MEDLINE (from 1950), EMBASE (from 1980), reference lists of articles and abstracts from conference proceedings without language restriction. Manufacturers' of methenamine salts were contacted for unpublished studies and contact was made with known investigators.Date of last search: June 2012

SELECTION CRITERIA

Randomised controlled trials (RCT) and quasi-RCTs of methenamine hippurate used for the prevention of UTIs in all population groups were eligible. A comparison with a control/no treatment group was a prerequisite for selection.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as risk ratio (RR) for dichotomous outcomes with 95% confidence intervals (CI). An exploration of heterogeneity and a detailed description of results, grouped by population, was undertaken.

MAIN RESULTS

Thirteen studies (2032 participants) were included. Six studies (654 patients) reported symptomatic UTI and eight studies (796 patients) reported bacteriuria. Overall, study quality was mixed. The overall pooled estimates for the major outcome measures were not interpretable because of underlying heterogeneity. Subgroup analyses suggested that methenamine hippurate may have some benefit in patients without renal tract abnormalities (symptomatic UTI: RR 0.24, 95% CI 0.07 to 0.89; bacteriuria: RR 0.56, 95% CI 0.37 to 0.83), but not in patients with known renal tract abnormalities (symptomatic UTI: RR 1.54, 95% CI 0.38 to 6.20; bacteriuria: RR 1.29, 95% CI 0.54 to 3.07). For short-term treatment duration (1 week or less) there was a significant reduction in symptomatic UTI in those without renal tract abnormalities (RR 0.14, 95% CI 0.05 to 0.38). The rate of adverse events was low.

AUTHORS' CONCLUSIONS

Methenamine hippurate may be effective for preventing UTI in patients without renal tract abnormalities, particularly when used for short-term prophylaxis. It does not appear to work in patients with neuropathic bladder or in patients who have renal tract abnormalities. The rate of adverse events was low, but poorly described.There is a need for further large well-conducted RCTs to clarify this question, particularly for longer term use for people without neuropathic bladder.

Methenamine hippurate for preventing urinary tract infections

BACKGROUND

Methenamine salts are often used as an alternative to antibiotics for the prevention of urinary tract infection (UTI). This review was first published in Issue 1, 2002 and updated in Issue 4, 2007.

OBJECTIVES

To assess the benefits and harms of methenamine hippurate in preventing UTI.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library), MEDLINE (from 1950), EMBASE (from 1980), reference lists of articles and abstracts from conference proceedings without language restriction. Manufacturers' of methenamine salts were contacted for unpublished studies and contact was made with known investigators.Date of last search: June 2012

SELECTION CRITERIA

Randomised controlled trials (RCT) and quasi-RCTs of methenamine hippurate used for the prevention of UTIs in all population groups were eligible. A comparison with a control/no treatment group was a prerequisite for selection.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as risk ratio (RR) for dichotomous outcomes with 95% confidence intervals (CI). An exploration of heterogeneity and a detailed description of results, grouped by population, was undertaken.

MAIN RESULTS

Thirteen studies (2032 participants) were included. Six studies (654 patients) reported symptomatic UTI and eight studies (796 patients) reported bacteriuria. Overall, study quality was mixed. The overall pooled estimates for the major outcome measures were not interpretable because of underlying heterogeneity. Subgroup analyses suggested that methenamine hippurate may have some benefit in patients without renal tract abnormalities (symptomatic UTI: RR 0.24, 95% CI 0.07 to 0.89; bacteriuria: RR 0.56, 95% CI 0.37 to 0.83), but not in patients with known renal tract abnormalities (symptomatic UTI: RR 1.54, 95% CI 0.38 to 6.20; bacteriuria: RR 1.29, 95% CI 0.54 to 3.07). For short-term treatment duration (1 week or less) there was a significant reduction in symptomatic UTI in those without renal tract abnormalities (RR 0.14, 95% CI 0.05 to 0.38). The rate of adverse events was low.

AUTHORS' CONCLUSIONS

Methenamine hippurate may be effective for preventing UTI in patients without renal tract abnormalities, particularly when used for short-term prophylaxis. It does not appear to work in patients with neuropathic bladder or in patients who have renal tract abnormalities. The rate of adverse events was low, but poorly described.There is a need for further large well-conducted RCTs to clarify this question, particularly for longer term use for people without neuropathic bladder.

Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America

Guidelines for the diagnosis, prevention, and management of persons with catheter-associated urinary tract infection (CA-UTI), both symptomatic and asymptomatic, were prepared by an Expert Panel of the Infectious Diseases Society of America. The evidence-based guidelines encompass diagnostic criteria, strategies to reduce the risk of CA-UTIs, strategies that have not been found to reduce the incidence of urinary infections, and management strategies for patients with catheter-associated asymptomatic bacteriuria or symptomatic urinary tract infection. These guidelines are intended for use by physicians in all medical specialties who perform direct patient care, with an emphasis on the care of patients in hospitals and long-term care facilities.

Methenamine hippurate for preventing urinary tract infections

BACKGROUND

Methenamine salts are often used as an alternative to antibiotics for the prevention of urinary tract infection (UTI).

OBJECTIVES

To assess the benefits and harms of methenamine hippurate in preventing UTI.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library), MEDLINE (from 1950), EMBASE (from 1980), reference lists of articles and abstracts from conference proceedings without language restriction. Manufacturers' of methenamine salts were contacted for unpublished studies and contact was made with known investigators. Date of last search: September 2006

SELECTION CRITERIA

Randomised controlled trials (RCT) and quasi-RCTs of methenamine hippurate used for the prevention of UTIs in all population groups were eligible. A comparison with a control/no treatment group was a prerequisite for selection.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) for dichotomous outcomes with 95% confidence intervals (CI). An exploration of heterogeneity and a detailed description of results, grouped by population, was undertaken.

MAIN RESULTS

Thirteen studies (2032 participants) were included. Six studies (654 patients) reported symptomatic UTI and eight studies (796 patients) reported bacteriuria. Overall, study quality was mixed. The overall pooled estimates for the major outcome measures were not interpretable because of underlying heterogeneity. Subgroup analyses suggested that methenamine hippurate may have some benefit in patients without renal tract abnormalities (symptomatic UTI: RR 0.24, 95% CI 0.07 to 0.89; bacteriuria: RR 0.56, 95% CI 0.37 to 0.83), but not in patients with known renal tract abnormalities (symptomatic UTI: RR 1.54, 95% CI 0.38 to 6.20; bacteriuria: RR 1.29, 95% CI 0.54 to 3.07). For short-term treatment duration (1 week or less) there was a significant reduction in symptomatic UTI in those without renal tract abnormalities (RR 0.14, 95% CI 0.05 to 0.38). The rate of adverse events was low.

AUTHORS' CONCLUSIONS

Methenamine hippurate may be effective for preventing UTI in patients without renal tract abnormalities, particularly when used for short-term prophylaxis. It does not appear to work in patients with neuropathic bladder or in patients who have renal tract abnormalities. The rate of adverse events was low, but poorly described. There is a need for further large well-conducted RCTs to clarify this question, particularly for longer term use for people without neuropathic bladder.

Methenamine hippurate for preventing urinary tract infections

BACKGROUND

Methenamine salts are often used for the prevention of urinary tract infection (UTI).

OBJECTIVES

To assess the effectiveness of methenamine hippurate in preventing UTI.

SEARCH STRATEGY

Published and unpublished randomised controlled trials were identified from the Cochrane Controlled Trials Register, MEDLINE, EMBASE, CINAHL, Current Contents, reference lists of review articles and retrieved trials. The manufacturers' of methenamine salts were contacted for unpublished studies and contact was made with known investigators in the area.

SELECTION CRITERIA

Randomised and quasi-randomised trials of methenamine hippurate used for the prevention of UTIs in all population groups were eligible for inclusion. A comparison with a control (no treatment) group was a prerequisite to selection.

DATA COLLECTION AND ANALYSIS

Two reviewers (BL and TB) performed independent assessment and data extraction using a standardised format. Discrepancies, methodological and interpretative issues were discussed with JS or JC. An exploration of heterogeneity as well as a detailed description of results grouped by population was conducted.

MAIN RESULTS

Eleven studies met the inclusion criteria. All trials were included in a descriptive analysis. Seven trials were included in meta-analyses. Four trials (199 patients) studied symptomatic bacteriuria and six trials (341 patients) studied bacteriuria as an outcome measure. Overall, trial quality was poor. The direction of six of the pooled trials was towards a favourable treatment effect from methenamine hippurate. Interpretation of the pooled estimates was not done in view of underlying heterogeneity. The study by Pettersson 1989 explained some, but not all, of the underlying heterogeneity. This study differed from all others by including patients with known upper renal tract abnormalities. Adverse reactions were mentioned by 10 studies. The rate of adverse events was low.

REVIEWER'S CONCLUSIONS

There is not enough evidence to conclusively support the use of methenamine hippurate for urinary prophylaxis. An exploration of heterogeneity raises the (hypothesis generating) possibility that methenamine hippurate may have some efficacy in patients without but not in patients with known upper renal tract abnormality (with asymptomatic bacteriuria as the outcome measure). Due to the small sample size and methodological problems within the studies involved, interpretation of these data should be done cautiously. The rate of adverse events reported by the trials was low, which suggests that current usage is unlikely to be causing significant harm.

Asepsis and out-patient cystoscopy

Cystoscopy was performed on a control group of 74 patients under full sterile precautions and on a study group of 83 patients under aseptic conditions, which required fewer materials. The incidence of urinary infections in the two groups was 4 and 6% respectively; this difference is not statistically significant. Rigors were rare in both groups (1%). The financial savings achieved by using an aseptic technique for out-patient cystoscopy are discussed.

The nonuse of urethral catheterization in the management of urinary incontinence in the teaching nursing home

A survey of all patients in a 527-bed skilled nursing facility was carried out to determine the prevalence of bladder catheterization. The institution surveyed is a teaching nursing home and rehabilitation center comprising three intermediate-stay and rehabilitation units of 126 beds and nine long-term care units. The institutional prevalence of recurrent urinary incontinence was 46 per cent, or 243 patients. The prevalence of chronic indwelling urethral catheters was 2.5 per cent, or 13 patients. The prevalence of urethral catheterization was further reduced to 1.5 per cent on the long-term care units, where the rate of recurrent urinary incontinence exceeded 60 per cent. The results of our survey were then compared with similar surveys at the institution during the years 1975 through 1980. Despite a fluctuating but increasing prevalence of incontinence over the years studied, a favorable trend was shown toward a reduction in the number of patients with indwelling urethral catheters. This study indicates that unless specific complicating factors are present, urinary incontinence in all but a very few of the elderly can be successfully managed without chronic indwelling catheterization. The authors believe that the introduction and growth of an education and research program in the nursing home environment has led to improvement in the standards of medical and nursing care.

A controlled trial of different treatment regimens in patients with urinary tract infections after lower urinary tract surgery

One hundred and four patients who developed urinary tract infections after catheterization for acute retention of urine and surgery of the bladder or urethra were randomly allocated to four treatment groups. Analysis of the results in 65 patients showed that co-trimoxazole and 1 g cephradine administered twice daily for 1 week were successful in eradicating the urinary tract infections in 93% and 88% of the patients, respectively. The same dose of cephradine administered 4-times a day eradicated 64% of the infections. In patients for whom no treatment was given, the original infection did not clear in 65%. Escherichia coli and coagulase-negative staphylococci were the commonest infecting organisms. The in vitro sensitivity testing of antibiotics did not correlate well with the successful eradication of the infecting organism.

Bacteriuria after out-patient cystoscopy

The presence of bacteriuria 48-72 hours after cystoscopy has been correlated with the sex and previous history of the patient, and with the use of chlorhexidine 1/5,000 and water as alternative irrigant solutions. The infection rate was higher in women than in men. Chlorhexidine in the irrigant solution protected against postoperative bacteriuria in patients who did not have a history of previous urinary infection, but did not do so where there was such history.