Analysis of change in patient-reported outcome measures with floor and ceiling effects using the multilevel Tobit model: a simulation study and an example from a National Joint Register using body mass index and the Oxford Hip Score

Objectives This study has three objectives. (1) Investigate the association between body mass index (BMI) and the efficacy of primary hip replacement using a patient-reported outcome measure (PROMs) with a measurement floor and ceiling, (2) Explore the performance of different estimation methods to...

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Main Authors: Yoav Ben-Shlomo, Andrew Judge, Michael R Whitehouse, Ashley W Blom, Adrian Sayers, Alex J MacGregor
Format: Article
Language:English
Published: BMJ Publishing Group 2020-08-01
Series:BMJ Open
Online Access:https://bmjopen.bmj.com/content/10/8/e033646.full
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author Yoav Ben-Shlomo
Andrew Judge
Michael R Whitehouse
Ashley W Blom
Adrian Sayers
Alex J MacGregor
author_facet Yoav Ben-Shlomo
Andrew Judge
Michael R Whitehouse
Ashley W Blom
Adrian Sayers
Alex J MacGregor
author_sort Yoav Ben-Shlomo
collection DOAJ
description Objectives This study has three objectives. (1) Investigate the association between body mass index (BMI) and the efficacy of primary hip replacement using a patient-reported outcome measure (PROMs) with a measurement floor and ceiling, (2) Explore the performance of different estimation methods to estimate change in PROMs score following surgery using a simulation study and real word data where data has measurement floors and ceilings and (3) Lastly, develop guidance for practising researchers on the analysis of PROMs in the presence of floor and ceiling effects.Design Simulation study and prospective national medical device register.Setting National Register of Joint Replacement and Medical Devices.Methods Using a Monte Carlo simulation study and data from a national joint replacement register (162 513 patients with pre- and post-surgery PROMs), we investigate simple approaches for the analysis of outcomes with floor and ceiling effects that are measured at two occasions: linear and Tobit regression (baseline adjusted analysis of covariance, change-score analysis, post-score analysis) in addition to linear and multilevel Tobit models.Primary outcome The primary outcome of interest is change in PROMs from pre-surgery to 6 months post-surgery.Results Analysis of data with floor and ceiling effects with models that fail to account for these features induce substantial bias. Single-level Tobit models only correct for floor or ceiling effects when the exposure of interest is not associated with the baseline score. In observational data scenarios, only multilevel Tobit models are capable of providing unbiased inferences.Conclusions Inferences from pre- post-studies that fail to account for floor and ceiling effects may induce spurious associations with substantial risk of bias. Multilevel Tobit models indicate the efficacy of total hip replacement is independent of BMI. Restricting access to total hip replacement based on a patients BMI can not be supported by the data.
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spelling doaj-art-1d7b63a1b0b0424fb3d012eaedec6b632024-12-02T06:30:13ZengBMJ Publishing GroupBMJ Open2044-60552020-08-0110810.1136/bmjopen-2019-033646Analysis of change in patient-reported outcome measures with floor and ceiling effects using the multilevel Tobit model: a simulation study and an example from a National Joint Register using body mass index and the Oxford Hip ScoreYoav Ben-Shlomo0Andrew Judge1Michael R Whitehouse2Ashley W Blom3Adrian Sayers4Alex J MacGregor5Population Health Sciences, University of Bristol Faculty of Health Sciences, Bristol, UK1 Musculoskeletal Research Unit, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UKMusculoskeletal Research Unit, University of Bristol, Bristol, UKTranslational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UKsenior research fellow in medical statisticsFaculty of Medicine and Health Sciences, University of East Anglia, Norwich, UKObjectives This study has three objectives. (1) Investigate the association between body mass index (BMI) and the efficacy of primary hip replacement using a patient-reported outcome measure (PROMs) with a measurement floor and ceiling, (2) Explore the performance of different estimation methods to estimate change in PROMs score following surgery using a simulation study and real word data where data has measurement floors and ceilings and (3) Lastly, develop guidance for practising researchers on the analysis of PROMs in the presence of floor and ceiling effects.Design Simulation study and prospective national medical device register.Setting National Register of Joint Replacement and Medical Devices.Methods Using a Monte Carlo simulation study and data from a national joint replacement register (162 513 patients with pre- and post-surgery PROMs), we investigate simple approaches for the analysis of outcomes with floor and ceiling effects that are measured at two occasions: linear and Tobit regression (baseline adjusted analysis of covariance, change-score analysis, post-score analysis) in addition to linear and multilevel Tobit models.Primary outcome The primary outcome of interest is change in PROMs from pre-surgery to 6 months post-surgery.Results Analysis of data with floor and ceiling effects with models that fail to account for these features induce substantial bias. Single-level Tobit models only correct for floor or ceiling effects when the exposure of interest is not associated with the baseline score. In observational data scenarios, only multilevel Tobit models are capable of providing unbiased inferences.Conclusions Inferences from pre- post-studies that fail to account for floor and ceiling effects may induce spurious associations with substantial risk of bias. Multilevel Tobit models indicate the efficacy of total hip replacement is independent of BMI. Restricting access to total hip replacement based on a patients BMI can not be supported by the data.https://bmjopen.bmj.com/content/10/8/e033646.full
spellingShingle Yoav Ben-Shlomo
Andrew Judge
Michael R Whitehouse
Ashley W Blom
Adrian Sayers
Alex J MacGregor
Analysis of change in patient-reported outcome measures with floor and ceiling effects using the multilevel Tobit model: a simulation study and an example from a National Joint Register using body mass index and the Oxford Hip Score
BMJ Open
title Analysis of change in patient-reported outcome measures with floor and ceiling effects using the multilevel Tobit model: a simulation study and an example from a National Joint Register using body mass index and the Oxford Hip Score
title_full Analysis of change in patient-reported outcome measures with floor and ceiling effects using the multilevel Tobit model: a simulation study and an example from a National Joint Register using body mass index and the Oxford Hip Score
title_fullStr Analysis of change in patient-reported outcome measures with floor and ceiling effects using the multilevel Tobit model: a simulation study and an example from a National Joint Register using body mass index and the Oxford Hip Score
title_full_unstemmed Analysis of change in patient-reported outcome measures with floor and ceiling effects using the multilevel Tobit model: a simulation study and an example from a National Joint Register using body mass index and the Oxford Hip Score
title_short Analysis of change in patient-reported outcome measures with floor and ceiling effects using the multilevel Tobit model: a simulation study and an example from a National Joint Register using body mass index and the Oxford Hip Score
title_sort analysis of change in patient reported outcome measures with floor and ceiling effects using the multilevel tobit model a simulation study and an example from a national joint register using body mass index and the oxford hip score
url https://bmjopen.bmj.com/content/10/8/e033646.full
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