Volume 13, Issue 4 (VOl 13, No.4, Winter 2018)                   irje 2018, 13(4): 356-361 | Back to browse issues page

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1- Associate Professor, Digestive Diseases Research Center, Digestive Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
2- Assistant Professor, Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences,Tehran, Iran
Abstract:   (4439 Views)
One of the traditional methods used for the analysis of survival data is the Cox regression technique. This method calculates the conditional risk ratio. However, when the aim of the study is to estimate the effect of exposure in the total population level, using these conditional methods is not apposite. Furthermore, the hazard ratio has disadvantages of its own such as being non-collapsible, having the risk of structural selection bias and variability in time. Given the limitations, it is recommended to use the marginal hazard ratio, which estimates the average causal effect of exposure in the total population level.
This study introduces the inverse probability treatment weighting (IPTW) as a method of estimating the marginal causal effect. Finally, to illustrate IPTW method, we used Golestan Cohort Study and estimated the marginal causal effect of smoking on time to death due to the upper gastrointestinal cancer (esophageal-gastric).
Full-Text [PDF 1557 kb]   (1229 Downloads)    
Type of Study: Review Article | Subject: General
Received: 2018/04/18 | Accepted: 2018/04/18 | Published: 2018/04/18