Household Water Treatment in Developing Countries: Comparing Different Intervention Types Using Meta-Regression
Household Water Treatment in Developing Countries: Comparing Different Intervention Types Using Meta-Regression
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DOI：
10.1021/es9028217
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发表时间：
2009-12-01
影响因子：
11.4
通讯作者：
Hunter, Paul R.
中科院分区：
文献类型：
--
作者：
Hunter, Paul R.
家庭水处理（HWT）作为减轻发展中国家贫困社区水传播疾病负担的适当干预措施正在得到广泛推广。最近的一项研究引起了人们对 HWT 有效性的担忧，部分原因是对缺乏盲法的担忧，部分原因是随机对照试验报告的有效性存在相当大的异质性。本研究试图调查这种异质性的原因，从而确定与良好健康收益相关的因素。早期系统评价和荟萃分析中确定的研究得到了最近发表的随机对照试验的补充。分析中纳入了总共 28 项独立的 HWT 随机对照试验研究，涉及 39 个干预组。使用 Stata 中的“metareg”命令研究异质性。对单个候选预测变量进行了初步分析，所有 P < 0.2 水平显着的变量都包含在最终的回归模型中。通过使用 @Risk 的蒙特卡罗建模和最终回归模型的参数估计，进行了进一步的分析，以估计干预措施随时间的影响。所有非盲研究的总体效应大小为相对风险 = 0.56（95% 置信区间 0.51-0.63），但由于缺乏盲法而调整偏倚后，效应大小要低得多（FIR = 0.85，95% Cl = 0.76-0.97）。四个主要变量是多预测元回归模型中干预有效性的显着预测因子：研究随访的对数持续时间（对数效应大小的回归系数= 0.186，标准误差（SE）= 0.072）、研究是否采用盲法（系数0.251，SE 0.066）以及在紧急情况下进行（系数-0.351，SE 0.076）都是效果的显着预测因子最终模型中的尺寸。与陶瓷过滤器相比，所有其他干预措施的效果都要差得多（Biosand 0.247, 0.073；氯和安全废物储存 0.295, 0.061；混凝剂-氯 0.2349, 0.067；SODIS 0.302, 0.068）。蒙特卡罗模型预测，超过 12 个月的陶瓷过滤器可能仍能有效减少疾病，而 SODIS、氯化和混凝氯化几乎没有任何益处。事实上，这三种干预措施预计将具有与预期相同或更少的效果，这纯粹是由于非盲研究中的报告偏差。根据目前可用的证据，陶瓷过滤器是长期最有效的 HWT 形式，包括 SODIS 在内的仅消毒干预措施似乎对公共健康的长期益处也很差。
Household water treatment (HWT) is being widely promoted as an appropriate intervention for reducing the burden of waterborne disease in poor communities in developing countries. A recent study has raised concerns about the effectiveness of HWT, in part because of concerns over the lack of blinding and in part because of considerable heterogeneity in the reported effectiveness of randomized controlled trials. This study set out to attempt to investigate the causes of this heterogeneity and so identify factors associated with good health gains. Studies identified in an earlier systematic review and meta-analysis were supplemented with more recently published randomized controlled trials. A total of 28 separate studies of randomized controlled trials of HWT with 39 intervention arms were included in the analysis. Heterogeneity was studied using the "metareg" command in Stata. Initial analyses with single candidate predictors were undertaken and all variables significant at the P < 0.2 level were included in a final regression model. Further analyses were done to estimate the effect of the interventions over time by MonteCarlo modeling using @Risk and the parameter estimates from the final regression model. The overall effect size of all unblinded studies was relative risk = 0.56 (95% confidence intervals 0.51-0.63), but after adjusting for bias due to lack of blinding the effect size was much lower (FIR = 0.85, 95% Cl = 0.76-0.97). Four main variables were significant predictors of effectiveness of intervention in a multipredictor meta regression model: Log duration of study follow-up (regression coefficient of log effect size = 0.186, standard error (SE) = 0.072), whether or not the study was blinded (coefficient 0.251, SE 0.066) and being conducted in an emergency setting (coefficient -0.351, SE 0.076) were all significant predictors of effect size in the final model. Compared to the ceramic filter all other interventions were much less effective (Biosand 0.247, 0.073; chlorine and safe waste storage 0.295, 0.061; combined coagulant-chlorine 0.2349, 0.067; SODIS 0.302, 0.068). A Monte Carlo model predicted that over 12 months ceramic filters were likely to be still effective at reducing disease, whereas SODIS, chlorination, and coagulation-chlorination had little if any benefit. Indeed these three interventions are predicted to have the same or less effect than what may be expected due purely to reporting bias in unblinded studies With the currently available evidence ceramic filters are the most effective form of HWT in the longterm, disinfection-only interventions including SODIS appear to have poor if any longterm public health benefit.