Factors Associated With Advanced Tricuspid Regurgitation After Left-Side Double Valve Replacement in Propensity-Score-Matched Analysis: Propensity Score Matching in Observational Studies

Abstract

In recent years, research has focused on the causality relationship between variables. It is possible to divide the variables in a causal relationship into two as “independent” variable(s) which is in the “cause” state and “dependent” variable(s) which is in the “result” state. The investigation of the effect of the change in the independent variable(s) on the dependent variable forms the basis of the causality structure. Researches on causality can be examined under two main headings as experimental and observational studies. Experimental studies, known as studies investigating the effectiveness of diagnosis and treatment methods, are studies conducted under conditions determined by the experimenter and in which the intervention to subjects/individuals is possible. For instance, in an experimental study in which the effect of the drug is investigated, the drug is given to the individuals and what type of changes it causes in the outcome variable (such as increased blood sugar due to the drug effect) are evaluated. Experimental studies, in which it is possible to partially control the factors affecting the outcome variable, can also be divided into studies with a control group and studies without a control group.