Open AccessPredicting the longitudinal changes of levodopa dose requirements in Parkinson’s disease using item response theory assessment of real‐world Unified Parkinson's Disease Rating Scale
Author(s) -
Chae Dongwoo,
Chung Su Jin,
Lee Phil Hyu,
Park Kyungsoo
Publication year - 2021
Publication title -
cpt: pharmacometrics and systems pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.53
H-Index - 37
ISSN - 2163-8306
DOI - 10.1002/psp4.12632
Subject(s) - rating scale , item response theory , parkinson's disease , levodopa , disease , psychology , longitudinal study , polytomous rasch model , physical medicine and rehabilitation , medicine , physical therapy , psychometrics , clinical psychology , developmental psychology , pathology
Item response theory (IRT) has been recently adopted to successfully characterize the progression of Parkinson's disease using serial Unified Parkinson's Disease Rating Scale (UPDRS) measurements. However, it has yet to be applied in predicting the longitudinal changes of levodopa dose requirements in the real‐world setting. Here we use IRT to extract two latent variables that represent tremor and non‐tremor‐related symptoms from baseline assessments of UPDRS Part III scores. We show that relative magnitudes of the two latent variables are strong predictors of the progressive increase of levodopa equivalent dose (LED). Retrospectively collected item‐level UPDRS Part III scores and longitudinal records of prescribed medication doses of 128 patients with de novo PD extracted from the electronic medical records were used for model building. Supplementary analysis based on a subset of 36 patients with at least three serial assessments of UPDRS Part III scores suggested that the two latent variables progress at significantly different rates. A web application was developed to facilitate the use of our model in making individualized predictions of future LED and disease progression.