Klein-Geltink J E, Rochon P A, Dyer S, Laxer M, Anderson G M
Institute for Clinical Evaluative Sciences, Toronto, ON, Canada.
J Clin Epidemiol. 2007 Aug;60(8):766-72. doi: 10.1016/j.jclinepi.2006.11.008. Epub 2007 Mar 26.
To describe techniques used to address confounding in published observational studies.
A systematic literature review identified studies using administrative or registry data to investigate health effects of drug therapies. Studies published from January 2001 to December 2005 came from BMJ, New England Journal of Medicine, Lancet, Annals of Internal Medicine, and JAMA. A structured abstraction form was used to collect information about confounding.
The search identified 29 studies. Twenty-two studies (76%) had 10,000 or more subjects and 18 (62%) used a mortality outcome. None mentioned use of a literature search to identify confounders, however, 28 (97%) listed confounders included, and 26 (90%) listed confounders not included in the study. Eighteen (62.1%) discussed the validity of confounder data. Most (22, or 76%) studies included a table with the distribution of confounders but none used effect size to assess imbalance between comparison groups. Almost all studies used regression techniques (28, or 97%); fewer used stratification (16, or 55%) or matching (four, or 14%) to address confounding. Eleven (40%) studies discussed sensitivity analyses.
Published cohort studies routinely include a list of potential confounders but there is room for improvement in confounder identification, measurement, and analysis.
描述已发表的观察性研究中用于处理混杂因素的技术。
一项系统文献综述确定了使用行政或登记数据来调查药物治疗对健康影响的研究。2001年1月至2005年12月发表的研究来自《英国医学杂志》《新英格兰医学杂志》《柳叶刀》《内科学年鉴》和《美国医学会杂志》。使用结构化摘要表收集有关混杂因素的信息。
检索到29项研究。22项研究（76%）有10000名或更多受试者，18项（62%）使用死亡率作为结局指标。然而，没有一项研究提及使用文献检索来识别混杂因素，不过，28项（97%）列出了纳入的混杂因素，26项（90%）列出了未纳入研究的混杂因素。18项（62.1%）讨论了混杂因素数据的有效性。大多数研究（22项，即76%）包含一个混杂因素分布表，但没有一项研究使用效应大小来评估比较组之间的不均衡。几乎所有研究都使用回归技术（28项，即97%）；较少使用分层（16项，即55%）或匹配（4项，即14%）来处理混杂因素。11项（40%）研究讨论了敏感性分析。
已发表的队列研究通常会列出潜在的混杂因素，但在混杂因素的识别、测量和分析方面仍有改进空间。
