Modelling treatment, age- and gender-specific recovery in acute injury studies
Akacha, Mouna, Hutton, Jane (Statistician) and Lamb, S. E. (Sallie E.) (2010) Modelling treatment, age- and gender-specific recovery in acute injury studies. Working Paper. Coventry: University of Warwick. Centre for Research in Statistical Methodology. Working papers, Vol.2010 (No.9).
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Official URL: http://www2.warwick.ac.uk/fac/sci/statistics/crism...
Background: Acute injury studies often measure physical ability repeatedly over
time through scores that have a finite range. This can result in a faster score change
at the beginning of the study than towards the end, motivating the investigation of
the rate of change. Additionally, the bounds of the score and their dependence on
covariates are often of interest.
Methods: We argue that transforming bounded data is not satisfactory in some
settings. Motivated by the Collaborative Ankle Support Trial (CAST), which investigated
different methods of immobilisation for severe ankle sprains, we developed a
model under the assumption that the recovery rate at a specific time is proportional to
the current score and the remaining score. This model enables a direct interpretation
of the covariate effects. We have re-analyzed the CAST data using these improved
methods, and explored novel relationships between age, gender and recovery rate.
Results: We confirm that using below knee cast is advantageous compared with a
tubular bandage in relation with the recovery rate. An age and gender effect on the
recovery rate and the maximum achievable score is demonstrated, with older female
patients recovering less fast (age-effect: -0.21, 95% confidence interval (CI) [-0.28,-
0.14]; gender effect: -0.06, CI [-0.12,-0.004]) and achieving a lower maximum score
(age-effect: -8.07, CI [-11.68,-4.01]; gender-effect: -5.34, CI [-8.18, -2.50]) than younger
Conclusions: Our model is able to accurately model repeated measurements on the
original scale, while accounting for the bounded nature of a score. We demonstrate
that recovery in acute injury trials can differ substantially by age and gender. Older
female patients are less likely to recover well from a sprain.
|Item Type:||Working or Discussion Paper (Working Paper)|
|Subjects:||Q Science > QA Mathematics
R Medicine > R Medicine (General)
|Divisions:||Faculty of Science > Statistics
Faculty of Medicine > Warwick Medical School
|Library of Congress Subject Headings (LCSH):||Medical statistics, Wounds and injuries -- Mathematical models, Medical rehabilitation -- Mathematical models|
|Series Name:||Working papers|
|Publisher:||University of Warwick. Centre for Research in Statistical Methodology|
|Place of Publication:||Coventry|
|Official Date:||May 2010|
|Number of Pages:||12|
|Status:||Not Peer Reviewed|
|Access rights to Published version:||Open Access|
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