Tuesday, 7 May 2013

Predicting Relapse

EpubMorgan et al. The magnetic resonance imaging 'rule of five': predicting the occurrence of relapse. Mult Scler. 2013 Apr.

BACKGROUND: Clinical intuition suggests that a sharp increase in the number of enhancing lesions should signal an increased risk of relapse. The 'rule of five' recommends that subjects exhibiting at least five lesions over the baseline level be referred for closer monitoring. This rule has been used as an informal safety criterion with limited formal evaluation.


OBJECTIVE: The purpose of this study was to determine the best threshold for the rule and to demonstrate its predictive validity for risk of subsequent relapses for multiple sclerosis (MS) trials.


METHODS: We used logistic regression modeling to apply the rule to patient data from a phase II clinical trial. Predictive validity was ascertained using rate ratios and receiver operating characteristic (ROC) curves.


RESULTS: We found that, for these data, a threshold of five lesions over the baseline constituted the best definition of a threshold. Overall, 35% of subjects broke the rule at least once. Breaking the rule increased the odds of imminent relapse by a factor of 3.2 (95% confidence interval (CI): 1.8-5.5).


CONCLUSION: Breaking the rule of five was found to be a significant predictor of an imminent relapse. Length of follow-up and the number of lesions discovered via magnetic resonance imaging (MRI) were also significant predictors of relapse.



Predicting relapses!

3 comments:

  1. How significant is the relapse? I thought anybody with enhancing lesions needs closer monitorung etc, with or without a relapse,

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    Replies
    1. How significant is the relapse?

      I agree lesions that cause relapse happen to occur in clinically eloquent sites. Active lesions in non-eloquent sites are just as important. This is why I now refer to these lesions as subclinical or asymptomatic relapses. My new moto is zero tolerance or Zeto; we need to suppress all inflammatory activity.

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    2. Since you mentioned lesions... do you have any explanation as to why lesions appear consequtively the one after the other? Why don't they appear in groups at once?

      http://www.med.harvard.edu/AANLIB/cases/case5/mr4/035.html

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