- 著者
- Shotaro Aso Hideo Yasunaga
- 出版者
- Society for Clinical Epidemiology
- 雑誌
- Annals of Clinical Epidemiology (ISSN:24344338)
- 巻号頁・発行日
- vol.2, no.3, pp.69-74, 2020 (Released:2020-07-01)
- 参考文献数
- 19
- 被引用文献数
- 7 16
In theory, instrumental variable (IV) analysis, like randomized controlled trials, can adjust for measured and unmeasured confounders. IVs need to meet the following three conditions: (i) they are associated with treatment assignment; (ii) they have no direct association with the outcome and are associated with the outcome exclusively through the treatment; and (iii) they are not associated with any of the measured confounders. Studies have presented several types of IV, including preferences of the facility or physician, differential distance, and days of the week. Two types of estimation method have been introduced: two-stage least squares and two-stage residual inclusion. The assumption of monotonicity limits the generalizability of estimates of causal effects in IV analysis because the target population of IV analysis is “compliers” (those who always comply with the assigned treatment). IV analysis using two or more IVs is feasible but requires the overidentifying restriction test. Despite several limitations, IV analysis is a feasible option that may be used for causal inference in comparative effectiveness studies using retrospective observational data.
- 著者
- Satoshi Kasuya Shotaro Aso Isao Takahashi
- 出版者
- Society for Clinical Epidemiology
- 雑誌
- Annals of Clinical Epidemiology (ISSN:24344338)
- 巻号頁・発行日
- vol.5, no.3, pp.74-79, 2023 (Released:2023-07-04)
- 参考文献数
- 15
BACKGROUNDExtracorporeal membrane oxygenation (ECMO) has been used for decades, but optimal anticoagulation control remains unknown. This study aimed to compare shorter target activated coagulation time (ACT) criteria with the usual target ACT criteria in terms of complications.METHODSWe retrospectively identified patients who received ECMO between 1 January 2013 and 31 December 2018 in an acute tertiary care hospital. Patients were divided into two groups: (I) those whose target ACT was 160–180 sec and (II) those whose target ACT was 180–220 sec. Cox proportional hazard models and Fine–Gray models adjusted for propensity score to account for the competing risk of death were used to compare the incidence of hemorrhage during ECMO between the groups.RESULTSWe identified 74 patients, 25 of whom were managed with target ACT 160–180 sec, and 49 of whom were managed with target ACT 180–220 sec. In crude analysis, the proportions of patients with hemorrhage in the under 180-sec group were significantly more than those in the over 180-sec group [60.0% (15/25) vs. 28.6% (14/49), p = 0.009]. Shorter target ACT was not associated with hemorrhage during ECMO in either Cox regression (hazard ratio, 1.67; 95% confidence interval, 0.59–4.80; p = 0.336) or Fine–Gray model (hazard ratio, 1.58; 95% confidence interval, 0.64–3.91; p = 0.324).CONCLUSIONSThe shorter ACT target was not associated with improved hemorrhage and inappropriate coagulation than the usual target ACT criteria. This study is the first to compare the ACT target of patients with ECMO.