Response to Letter Regarding Article, “Standard-Dose Intravenous Tissue-Type Plasminogen Activator for Stroke Is Better Than Low Doses”

We thank Doctor Chao et al for their advices on our recent study that whether lower-dose intravenous tissue-type plasminogen activator (tPA) for stroke is as effective and safe as the standard dose.1When we want to compare the outcomes of ≥2 treatment groups for nonrandomized study, we must adjust the difference of baseline variables. Usually, there are 2 methods for choosing baseline variables included in the multivariable model for calculating adjusted odds ratio. First, we can just choose all significant baseline variables in the univariable analysis. Second, we can choose all possible variables that may affect outcomes according to our clinical experience or the result of other studies. Which of the 2 methods is good is still a matter of debate. But the number of variables you can choose …