Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom.
Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom ; Department of Geriatric Medicine, University of Auckland, Auckland, New Zealand.
PLoS One. 2013 Dec 20;8(12):e83203. doi: 10.1371/journal.pone.0083203. eCollection 2013.
Animal studies have demonstrated macrogol laxatives may reduce colorectal cancer (CRC) risk. This study aimed to investigate the association between macrogol prescribing and CRC risk.
A case-control study nested within a cohort of laxative users was conducted using data from the UK General Practice Research Database. Six controls per case were identified and to account for the lead time of CRC, additional control sets were selected on the index date backdated by 1 to 5 years. Exposure to macrogols and covariate status before each of the backdated index dates was established. Conditional logistic regression was used to calculate the risk of CRC following macrogol prescribing adjusted for potential confounders.
4734 incident CRC cases were identified; 2722, 2195, 1789, 1481 and 1214 had received a laxative prescription before the index dates backdated by 1 to 5 years. A suggestion of a non-significant reduction in CRC risk associated with 'macrogol after other laxative' prescribing was observed when the index date was backdated by 1 and 2 years, ORadj = 0.87 (CI950.74-1.03) and ORadj = 0.80 (CI950.65-1.00) compared to non-macrogol laxative exposure. The odds ratios reduced further and were significant when backdated by 3, 4 and 5 years, ORadj = 0.68 (CI950.50-0.92), ORadj = 0.60 (CI950.40-0.90) and ORadj = 0.30 (CI950.14-0.64) respectively. This reduction in risk was not observed, however, for 'macrogol only' and 'macrogol before other laxative' exposure categories.
In this study we observed a reduced CRC risk associated with macrogol prescribing after accounting for the lead time for CRC. Further studies are required to determine whether the association is causal and whether it can partly be explained by selective prescribing.
动物研究表明，聚乙二醇泻药可能降低结直肠癌（CRC）风险。本研究旨在探讨聚乙二醇处方与 CRC 风险之间的关联。
本病例对照研究嵌套在泻药使用者队列中，使用来自英国普通实践研究数据库的数据。每例病例匹配 6 名对照，并为了考虑 CRC 的领先时间，在索引日期前回退 1 至 5 年选择额外的对照集。在每个回退索引日期之前确定聚乙二醇暴露和协变量状态。使用条件逻辑回归计算调整潜在混杂因素后聚乙二醇处方后 CRC 的风险。
共确定了 4734 例 CRC 新发病例；2722、2195、1789、1481 和 1214 例在回退 1 至 5 年的索引日期前接受了泻药处方。当索引日期回退 1 年和 2 年时，观察到与“其他泻药后聚乙二醇”处方相关的 CRC 风险呈非显著降低趋势，ORadj=0.87（95%CI0.74-1.03）和 ORadj=0.80（95%CI0.65-1.00）与非聚乙二醇泻药暴露相比。当回退 3、4 和 5 年时，比值比进一步降低且具有统计学意义，ORadj=0.68（95%CI0.50-0.92）、ORadj=0.60（95%CI0.40-0.90）和 ORadj=0.30（95%CI0.14-0.64）。然而，对于“仅聚乙二醇”和“聚乙二醇前其他泻药”暴露类别，未观察到这种风险降低。
在本研究中，我们观察到在考虑 CRC 的领先时间后，聚乙二醇处方与 CRC 风险降低相关。需要进一步的研究来确定这种关联是否是因果关系，以及它是否可以部分解释为选择性处方。
