Abstract
Despite the advent of sophisticated imaging systems, plain radiography continues to be a valuable outcome variable in clinical trials of inflammatory disorders for a number of reasons. This paper discusses the pros and cons of the different ways in which radiographic data in trials is presented; the minimum time needed to demonstrate radiographic progression in the context of a clinical trial; and the best ways to statistically analyse radiographic data.
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Figure 1.
Probability plots representing one year radiographic progression in both groups of the COBRA study (see table 1 footnote for details). Every symbol represents the score of an individual, and all scores are plotted against their cumulative probability.
Figure 2.
Probability plot of an imaginary progression scenario. Negative progression scores do not necessarily imply repair. Every individual score represents a combination of true change and measurement error. It is impossible to distinguish both at the individual patient level.
Figure 3.
(A) Probability plots of progression scores obtained from a three month clinical trial, in which sets of radiographs were scored with known time order (chronological; red) and with unknown time order (paired; blue). (B, C) Probability plots of progression scores obtained from a three month clinical trial in which sets of radiographs were scored with known time order (chronological; B) and with unknown time order (paired; C), stratified for the presence (blue) or absence (red) of radiographic damage at baseline.
Selected References
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