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The Kaplan-Meier method is often used to analyze survival rates, but is there any other analysis method?
Direct method covering all subjects
The best method to calculate the survival rate after 3 years is to check the life and death status of all patients who received the drug.
For example, in the case of a clinical trial of drug A, only the cases that have survived three years from the start date of observation are counted, and the percentage of surviving patients is determined. Such a method is called a “direct method.”
Survival rates are difficult to assess if there is a premature censoring among the subjects. If the reason for the discontinuation affects the patient’s prognosis, excluding this from the calculation leads to a biased survival rate. The true survival rate must be taken between the value where all censoring is considered as surviving, and that where all are dead. However, in actual clinical trials, it is almost impossible to properly enroll and follow up with patients in this way.
When the number of cases was large, a method called life insurance actuarial method was also used
In addition to the direct method, there is a calculation method for the measured survival rate, called “life insurance actuarial method.” This can include cases of discontinuation in the aggregate. In the past, when the number of cases was large, the life insurance actuarial method was recommended, and when the number of cases was small, the Kaplan-Meier method was recommended. Today, however, with significant improvement in the tabulation functions of computers, even if there are tens of thousands of cases, calculations can be easily performed using the Kaplan-Meier method.
Since the Kaplan-Meier method is statistically superior, it is now recommended for use.
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