Neutrophil Gelatinase-Associated Lipocalin Biomarker and Urinary Tract Infections: A Diagnostic Case-Control Study (NUTI Study).

OBJECTIVES: Acute uncomplicated urinary tract infection (UTI) in women is often treated based on symptoms alone. Urinary tract infection symptoms are highly sensitive but lack specificity and result in overuse of antibiotics. We sought to determine if urine neutrophil gelatinase-associated lipocalin (uNGAL) levels in urine can accurately discriminate between UTI and healthy women. METHODS: We recruited adult women aged 18 to 85 years presenting in the ambulatory setting from November 2014 to January 2016. Cases were defined as women with Centers for Disease Control and Prevention-defined UTI symptoms and a positive urine culture of more than 10 organisms/mL on a midstream clean-catch specimen. Women without UTI symptoms were matched by age and menopausal status as control subjects. Exclusion criteria were no UTIs within 8 weeks, urinary tract anomalies, renal disease, pregnancy, or diabetes. Clean-catch urine samples were obtained for measuring uNGAL, prior to antibiotic treatment of cases. We used Mann-Whitney U test to compare the 2 groups. Receiver operating characteristic curves were plotted to compare the performance of uNGAL to established urinary markers. RESULTS: We enrolled 50 UTI cases and 50 control subjects. Urine NGAL levels were higher in the UTI group than in the control subjects (P < 0.0001). Using a cutoff of 23.9 ng/mL, NGAL achieved 98% sensitivity and 100% specificity. The receiver operating characteristic curve had an area under the curve of 0.97 (95% confidence interval, 0.93-1.00), which was significantly high and showed that uNGAL can identify UTI. CONCLUSIONS: Urine NGAL has the potential as a biomarker for diagnosing UTIs in adult women.

Nitrofurantoin vs other prophylactic agents in reducing recurrent urinary tract infections in adult women: a systematic review and meta-analysis.

BACKGROUND: The clinical and financial burden from bladder infections is significant. Daily antibiotic use is the recommended strategy for recurrent urinary tract infection prevention. Increasing antibiotic resistance rates, however, require immediate identification of innovative alternative prophylactic therapies. This systematic review aims to provide guidance on gaps in evidence to guide future research. OBJECTIVE: The objective of this review was to provide current pooled estimates of randomized control trials comparing the effects of nitrofurantoin vs other agents in reducing recurrent urinary tract infections in adult, nonpregnant women and assess relative adverse side effects. DATA SOURCES: Data sources included the following: MEDLINE, Jan. 1, 1946, to Jan. 31, 2015; Cochrane Central Register of Controlled Trials the Cochrane Database of Systematic Reviews, and web sites of the National Institute for Clinical Excellence, and the National Guideline Clearinghouse from 2000 to 2015. Randomized control trials of women with recurrent urinary tract infections comparing nitrofurantoin with any other treatment were included. STUDY DESIGN: A protocol for the study was developed a priori. Published guidance was followed for assessment of study quality. All meta-analyses were performed using random-effects models with Stats Direct Software. Dual review was used for all decisions and data abstraction. RESULTS: Twelve randomized control trials involving 1063 patients were included. One study that had a serious flaw was rated poor in quality, one study rated good, and the remainder fair. No significant differences in prophylactic antibiotic treatment with nitrofurantoin and norfloxacin, trimethoprim, sulfamethoxazole/trimethoprim, methamine hippurate, estriol, or cefaclor were found in clinical or microbiological cure in adult nonpregnant women with recurrent urinary tract infections (9 randomized control trials, 673 patients, relative risk ratio, 1.06; 95% confidence interval, 0.89-1.27; I2, 65%; and 12 randomized control trials, 1063 patients, relative risk ratio, 1.06; 95% confidence interval, 0.90-1.26; I2, 76%, respectively). Duration of prophylaxis also did not have a significant impact on outcomes. There was a statistically significant difference in overall adverse effects, with nitrofurantoin resulting in greater risk than other prophylactic treatments (10 randomized control trials, 948 patients, relative risk ratio, 2.17; 95% confidence interval, 1.34-3.50; I2, 61%). Overall, the majority of nitrofurantoin adverse effects were gastrointestinal, with a significant difference for withdrawals (12 randomized control trials, 1063 patients, relative risk ratio, 2.14; 95% confidence interval, 1.28-3.56; I2, 8%). CONCLUSION: Nitrofurantoin had similar efficacy but a greater risk of adverse events than other prophylactic treatments. Balancing the risks of adverse events, particularly gastrointestinal symptoms, with potential benefits of decreasing collateral ecological damage should be considered if selecting nitrofurantoin.