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A maximum likelihood estimator of a Markov model for disease activity in Crohn's disease and ulcerative colitis for annually aggregated partial observations.

Borg, Sixten LU ; Persson, Ulf LU ; Jess, Tine; Østergaard Thomsen, Ole; Ljung, Tryggve; Riis, Lene and Munkholm, Pia (2010) In Medical Decision Making 30(1). p.42-132
Abstract
Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory bowel diseases that have a remitting, relapsing nature. During relapse, they are treated with drugs and surgery. The present study was based on individual data from patients diagnosed with CD or UC at Herlev University Hospital, Copenhagen, Denmark, during 1991 to 1993. The data were aggregated over calendar years; for each year, the number of relapses and the number of surgical operations were recorded. Our aim was to estimate Markov models for disease activity in CD and UC, in terms of relapse and remission, with a cycle length of 1 month. The purpose of these models was to enable evaluation of interventions that would shorten relapses or postpone future relapses.... (More)
Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory bowel diseases that have a remitting, relapsing nature. During relapse, they are treated with drugs and surgery. The present study was based on individual data from patients diagnosed with CD or UC at Herlev University Hospital, Copenhagen, Denmark, during 1991 to 1993. The data were aggregated over calendar years; for each year, the number of relapses and the number of surgical operations were recorded. Our aim was to estimate Markov models for disease activity in CD and UC, in terms of relapse and remission, with a cycle length of 1 month. The purpose of these models was to enable evaluation of interventions that would shorten relapses or postpone future relapses. An exact maximum likelihood estimator was developed that disaggregates the yearly observations into monthly transition probabilities between remission and relapse. These probabilities were allowed to be dependent on the time since start of relapse and on the time since start of remission, respectively. The estimator, initially slow, was successfully optimized to shorten the execution time. The estimated disease activity model for CD fits well to observed data and has good face validity. The disease activity model is less suitable for UC due to its transient nature through the presence of curative surgery. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
maximum likelihood estimator, aggregated and partial observations, Markov model, transition probability matrix, inflammatory bowel disease, disease activity
in
Medical Decision Making
volume
30
issue
1
pages
42 - 132
publisher
SAGE Publications Inc.
external identifiers
  • scopus:75949085042
ISSN
1552-681X
DOI
10.1177/0272989X09336141
language
English
LU publication?
yes
id
f7d2c3c9-8b9c-4824-91d9-ed74d77e6e32 (old id 4058067)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/?term=19605883
date added to LUP
2013-09-24 14:53:17
date last changed
2018-05-29 10:54:56
@article{f7d2c3c9-8b9c-4824-91d9-ed74d77e6e32,
  abstract     = {Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory bowel diseases that have a remitting, relapsing nature. During relapse, they are treated with drugs and surgery. The present study was based on individual data from patients diagnosed with CD or UC at Herlev University Hospital, Copenhagen, Denmark, during 1991 to 1993. The data were aggregated over calendar years; for each year, the number of relapses and the number of surgical operations were recorded. Our aim was to estimate Markov models for disease activity in CD and UC, in terms of relapse and remission, with a cycle length of 1 month. The purpose of these models was to enable evaluation of interventions that would shorten relapses or postpone future relapses. An exact maximum likelihood estimator was developed that disaggregates the yearly observations into monthly transition probabilities between remission and relapse. These probabilities were allowed to be dependent on the time since start of relapse and on the time since start of remission, respectively. The estimator, initially slow, was successfully optimized to shorten the execution time. The estimated disease activity model for CD fits well to observed data and has good face validity. The disease activity model is less suitable for UC due to its transient nature through the presence of curative surgery.},
  author       = {Borg, Sixten and Persson, Ulf and Jess, Tine and Østergaard Thomsen, Ole and Ljung, Tryggve and Riis, Lene and Munkholm, Pia},
  issn         = {1552-681X},
  keyword      = {maximum likelihood estimator,aggregated and partial observations,Markov model,transition probability matrix,inflammatory bowel disease,disease activity},
  language     = {eng},
  number       = {1},
  pages        = {42--132},
  publisher    = {SAGE Publications Inc.},
  series       = {Medical Decision Making},
  title        = {A maximum likelihood estimator of a Markov model for disease activity in Crohn's disease and ulcerative colitis for annually aggregated partial observations.},
  url          = {http://dx.doi.org/10.1177/0272989X09336141},
  volume       = {30},
  year         = {2010},
}