A most stubborn bias: no adjustment method fully resolves confounding by indication in observational studies.
A most stubborn bias: no adjustment method fully resolves confounding by indication in observational studies.
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DOI：
10.1016/j.jclinepi.2009.03.001
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发表时间：
2010-01
影响因子：
7.2
通讯作者：
Lash, Timothy L.
中科院分区：
文献类型：
--
作者：
Bosco, Jaclyn L. F.;Silliman, Rebecca A.;Thwin, Soe Soe;Geiger, Ann M.;Buist, Diana S. M.;Prout, Marianne N.;Yood, Marianne Ulcickas;Haque, Reina;Wei, Feifei;Lash, Timothy L.
关键词：
To evaluate the effectiveness of methods that control for confounding by indication, we compared breast cancer recurrence rates among women receiving adjuvant chemotherapy versus those who did not. In a medical record review-based study of breast cancer treatment in older women (n=1798) diagnosed 1990-1994, our crude analysis suggested adjuvant chemotherapy was positively associated with recurrence [hazard ratio (HR)=2.6 (95% confidence interval (CI)=1.9, 3.5)]. We expected a protective effect, so postulated that the crude association was confounded by indications for chemotherapy. We attempted to adjust for this confounding by restriction, multivariable regression, propensity scores [PS], and instrumental variable [IV] methods. After restricting to women at high-risk for recurrence (n=946), chemotherapy was not associated with recurrence [HR=1.1 (95% CI=0.7, 1.6)] using multivariable regression. PS adjustment yielded similar results [HR=1.3 (95% CI=0.8, 2.0)]. The IV-like method yielded a protective estimate [HR=0.9; (95% CI=0.2, 4.3)]; however imbalances of measured factors across levels of the IV suggested residual confounding. Conventional methods do not control for unmeasured factors, which often remain important when addressing confounding by indication. PS and IV analysis methods can be useful under specific situations, but neither method adequately controlled confounding by indication in this study.
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影响因子：
5
作者：
Cepeda, MS;Boston, R;Strom, BL
通讯作者：
Strom, BL
DOI：
10.7326/0003-4819-127-8_part_2-199710151-00064
发表时间：
1997-10-15
影响因子：
39.2
作者：
Rubin, DB
通讯作者：
Rubin, DB
影响因子：
5
作者：
Schmoor, Claudia;Caputo, Angelika;Schumacher, Martin
通讯作者：
Schumacher, Martin
影响因子：
7.7
作者：
Greenland, S
通讯作者：
Greenland, S
影响因子：
5.4
作者：
Brookhart, MA;Wang, PS;Schneeweiss, S
通讯作者：
Schneeweiss, S