Designing Studies for Dose Response
Designing Studies for Dose Response
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设计剂量反应研究
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发表时间:
1996
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通讯作者:
P. Lachenbruch
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作者:
W. Wong;P. Lachenbruch
STATISTICS IN MEDICINE, VOL. 15, 343-359 (1996) TUTORIAL IN BIOSTATISTICS DESIGNING STUDIES FOR DOSE RESPONSE WENG KEE WONG UCLA Department of Biostatistics. Los Angeles, CA 90024-1 772, U.S.A. AND PETER A. LACHENBRUCH FDAICBERIOELPS HFM-215, 1401 Rockville Pike, Rockuille, M D 20852, U.S.A. SUMMARY ‘Dose response’ refers to the regression of a response on a stimulus. We review a number of options for doseresponse designs, and compare various designs which may be used in practice. We start with two group designs. Next, we introduce basic optimal approximate design theory for simple linear and quadratic regression illustrating different criteria of optimality and their effect on the allocation of the levels of the dose. Then we obtain the efficiencies of these optimal approximate designs and some simple designs which have intuitive appeal (symmetry, equal spacing of treatments, reduced numbers of observations at the highest and lowest doses). 1. INTRODUCTION The regression of response on stimulus may be represented graphically as a curve [as in Figure 11. When the stimulus is in the form of a ‘dose’(e.g., of a drug, or possibly of an applied force or some other source), this may be called a ‘dose response curve’. (Kotz and Johnson’). In its simplest form, a dose-response curve is a simple linear or polynomial regression. More complex ‘dose-response’ curves may involve, for example, a transcendental function. Others may involve transformations of the dose in the regressions. For example, dose-response models often use the logarithm of dose. This function of the dose is called the dose metameter. In some cases, the response is quanta1 (yes/no) and the dose-response technique is a probit analysis or logit analysis. Figure 1 shows dose-response curves for linear and quadratic models. The determination of a threshold dose is also a dose-response problem (see Figure 1). Here the response is A below a dose xo and B above that point. That is, the model is E( Y Ix) = A if x < xo and E( Y Ix) = B if x 2 xo where E( Y Ix) is the expected value of the response Y given X = x. The model requires that we estimate the value of xo, A and B. In this tutorial paper we will consider the dose-response cases in which response and the dose are continuous and the regression functions are either simple linear or quadratic models, that is E(Ylx) = A + Bx or E ( Y ( x )= A + BX + CX’. We also assume throughout that x is coded so that 0 < x CCC 0277-6715/96/040343-17 0 1996 by John Wiley & Sons, Ltd.