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Methenamine hippurate for preventing urinary tract infections

  • Review
  • Intervention

Authors


Abstract

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 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 Manufacturers' of methenamine salts were contacted for unpublished studies and contact was made with known investigators.

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.

摘要

背景

四氮六甲環 (Methenamine hippurate) 預防泌尿道感染

四氮六甲環鹽類通常被用來預防泌尿道感染 (UTI) 之抗生素替代物。

目標

評估四氮六甲鹽在預防泌尿道感染之益處與壞處

搜尋策略

我們搜尋了Cochrane對照試驗註冊資料庫 (於Cochrane Library資料庫中) ,MEDLINE (從1950) ,EMBASE (從1980) ,參考文獻清單和研討會公報摘要,且不論各種語言。聯絡未出版的研究之四氮六甲環鹽廠商和調查員。最近搜尋日期為2006年9月。

選擇標準

隨機對照試驗和半隨機對照試驗在用四氮六甲環鹽在所有人預防泌尿道感染皆適當。選擇的一個先決條件是有一個對照組/無治療組來比較。

資料收集與分析

兩位評審獨立地評估試驗品質及從各試驗中被選用的資料。統計分析是運用隨機作用模式,而分岐的結果則以相對風險 (RR) 和95% 的信賴區間 (CI) 來表示。探索異質性和詳細描述的結果,宜人口來分組。

主要結論

包括了13個研究 (2032病人) 其中6個研究 (654 病人) 在有症狀之泌尿道感染和8個研究 (796病人) 在有菌尿症。大體上研究的品質是混合。由於原有的異質性,主要成果的總聚合概算無法分析。小群分析建議四氮六甲環鹽可能對沒有泌尿道結構異常之病人有些好處 (有症狀之UTI: RR 0.24, 95% CI 0.07 – 0.89; 菌尿症: RR 0.56, 95% CI 0.37 – 0.83) ,但在有泌尿道結構異常病人未知 (有症狀之UTI: RR 1.54, 95% CI 0.38 – 6.20; 菌尿症: RR 1.29, 95% CI 0.54 – 3.07) 。短期間治療 (一週內) 在沒有泌尿道異常的病人,有明顯減少有症狀之泌尿道感染 (RR 0.14, 95% CI 0.05 – 0.38) 。不良事件也是較低的。

作者結論

四氮六甲環鹽可能在預防無泌尿道結構異常病人之泌尿道感染是有效的,特別在短期預防上。它通常不用在有神經性膀胱或有泌尿道結構異常之病人。不良事件發生率是很低,但很難描述。為無神經性膀胱病人的長期預防之效用,需更多的高效隨機對照試驗來證明。

翻譯人

本摘要由馬偕醫院徐正義翻譯。

此翻譯計畫由臺灣國家衛生研究院 (National Health Research Institutes, Taiwan) 統籌。

總結

膀胱和腎臟感染(泌尿道感染UTI)可引起噁吐,疼痛,排尿困難,敗血症,發燒和疲倦,和偶爾腎損傷。有些人屬於高危險群,且他們也更容易出現嚴重並發症(包括有腎臟疾病的人,或使用導尿管者)。長期使用抗生素會導致抗藥性,所以四氮鹽(四氮或六甲環)是經常被使用。13個研究 (2032病人) 被列入此文獻分析。四氮六甲環鹽可能在預防無泌尿道結構異常病人之泌尿道感染是有效的,特別在短期預防上。它可無效用在有神經性膀胱之病人的長期預防上。不良事件發生率是低。為無神經性膀胱病人的長期預防之效用,需更多的高級隨機對照試驗來證明。

Plain language summary

Methenamine hippurate for preventing urinary tract infections

Bladder and kidney infections (urinary tract infections - UTI) can cause vomiting, pain, dysuria, septicaemia, fever and tiredness, and occasionally kidney damage. Some people are at high risk of repeated UTIs, and they are also more likely to have serious complications (including people with kidney problems, or people who have catheters to release urine). Long-term use of antibiotics can lead to resistance, so methenamine salts (methenamine or hexamine hippurate) are often used. This review identified 13 studies (2032 participants). Methenamine hippurate may be effective in preventing UTI in patients without renal tract abnormalities particularly when used for short term prophylaxis. It does not appear to be effective for long term prophylaxis in patients who have neuropathic bladder. There were few adverse effects.Additional well controlled randomised controlled trials are necessary in particular to clarify effectiveness for longer term prophylaxis in those without neuropathic bladder.

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