Comment on “Modeling the Growth of Infrarenal Abdominal Aortic Aneurysms” by Bailey et al.

[摘要] The authors [1] have provided some interesting results and furthered understanding of the statistical challenges and appropriate procedures for estimating aneurysm growth rates. We have learned a great deal from this study and applaud their efforts. But after reviewing their study carefully, we feel that an exponential modeling approach, as applied in some previous research [2,3], is preferable because it models a more realistic pattern of aneurysm growth, in which growth depends not only on duration but on initial aneurysm size. The exponential model posits that the last measured aneurysm size, Al , and the first measured size, Af , are related as follows: (1) Al Af eT , (1) where T the time between the first and last tests and is a coefficient to be estimated. This approach is implemented by taking the natural logarithm of both sides of Equation 1 and then estimating by ordinary least squares (OLS), allowing for no intercept term. This functional relationship has the properties that aneurysm growth is larger, the greater the initial aneurysm size and the longer the patient is followed.