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Validation, test-retest reliability and norm scores for the Dutch Catquest-9SF

Visser, Martijn S.; Dieleman, Myrthe; Klijn, Stijn; Timman, Reinier; Lundström, Mats LU ; Busschbach, Jan J V and Reus, Nicolaas J. (2017) In Acta Ophthalmologica 95(3). p.312-319
Abstract

Purpose: The Catquest-9SF questionnaire is a unidimensional, reliable, valid and short patient-reported outcome measure for quantifying benefits in visual functioning from cataract surgery. Our aim was to develop a formal Dutch translation, calculate norm scores, assess its validity and test-retest reliability and provide an easy way for use in clinical practice. Methods: Translation of the questionnaire was performed according to guidelines of the International Society for Pharmacoeconomics and Outcomes Research. Catquest-9SF was obtained in 657 patients pre- and postcataract surgery. We applied Rasch and classical analyses to determine the questionnaire performance with characteristics such as unidimensionality, reliability,... (More)

Purpose: The Catquest-9SF questionnaire is a unidimensional, reliable, valid and short patient-reported outcome measure for quantifying benefits in visual functioning from cataract surgery. Our aim was to develop a formal Dutch translation, calculate norm scores, assess its validity and test-retest reliability and provide an easy way for use in clinical practice. Methods: Translation of the questionnaire was performed according to guidelines of the International Society for Pharmacoeconomics and Outcomes Research. Catquest-9SF was obtained in 657 patients pre- and postcataract surgery. We applied Rasch and classical analyses to determine the questionnaire performance with characteristics such as unidimensionality, reliability, separation and differential item functioning. Test-retest reliability was assessed in another group of 145 patients. A cut-off value to discriminate between people with and without cataract, norm scores and a reliable change index (RCI) were calculated using data from a sample of 916 'healthy' persons from the normal population. Results: The Dutch Catquest-9SF was unidimensional, and both person and item reliability were high; 0.87 and 0.99, respectively. Cronbach's alpha was 0.94, test-retest reliability was 0.85 and the intraclass correlation coefficient was 0.93. Catquest-9SF showed to be responsive to the effect of cataract surgery (effect size = 1.27; p < 0.001). The cut-off value was -1.90, and RCI was 2.27. A quick-access table with norm scores and percentiles was established to facilitate clinical interpretation. Conclusion: This investigation provides validity and reliability of the Dutch Catquest-9SF as well as norm scores and a new tool to facilitate the clinical interpretation of patient scores. This makes Catquest-9SF suitable for routine use in clinical practice.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Norm scores, Patient related outcome measures, Quality of life, Questionnaire, Test-retest reliability
in
Acta Ophthalmologica
volume
95
issue
3
pages
312 - 319
publisher
Wiley-Blackwell
external identifiers
  • scopus:84996940139
  • wos:000399359400037
ISSN
1755-375X
DOI
10.1111/aos.13287
language
English
LU publication?
yes
id
433c1c2d-2fe0-4838-ab94-d5b10ae11dec
date added to LUP
2016-12-30 13:56:58
date last changed
2018-01-07 11:43:33
@article{433c1c2d-2fe0-4838-ab94-d5b10ae11dec,
  abstract     = {<p>Purpose: The Catquest-9SF questionnaire is a unidimensional, reliable, valid and short patient-reported outcome measure for quantifying benefits in visual functioning from cataract surgery. Our aim was to develop a formal Dutch translation, calculate norm scores, assess its validity and test-retest reliability and provide an easy way for use in clinical practice. Methods: Translation of the questionnaire was performed according to guidelines of the International Society for Pharmacoeconomics and Outcomes Research. Catquest-9SF was obtained in 657 patients pre- and postcataract surgery. We applied Rasch and classical analyses to determine the questionnaire performance with characteristics such as unidimensionality, reliability, separation and differential item functioning. Test-retest reliability was assessed in another group of 145 patients. A cut-off value to discriminate between people with and without cataract, norm scores and a reliable change index (RCI) were calculated using data from a sample of 916 'healthy' persons from the normal population. Results: The Dutch Catquest-9SF was unidimensional, and both person and item reliability were high; 0.87 and 0.99, respectively. Cronbach's alpha was 0.94, test-retest reliability was 0.85 and the intraclass correlation coefficient was 0.93. Catquest-9SF showed to be responsive to the effect of cataract surgery (effect size = 1.27; p &lt; 0.001). The cut-off value was -1.90, and RCI was 2.27. A quick-access table with norm scores and percentiles was established to facilitate clinical interpretation. Conclusion: This investigation provides validity and reliability of the Dutch Catquest-9SF as well as norm scores and a new tool to facilitate the clinical interpretation of patient scores. This makes Catquest-9SF suitable for routine use in clinical practice.</p>},
  author       = {Visser, Martijn S. and Dieleman, Myrthe and Klijn, Stijn and Timman, Reinier and Lundström, Mats and Busschbach, Jan J V and Reus, Nicolaas J.},
  issn         = {1755-375X},
  keyword      = {Norm scores,Patient related outcome measures,Quality of life,Questionnaire,Test-retest reliability},
  language     = {eng},
  number       = {3},
  pages        = {312--319},
  publisher    = {Wiley-Blackwell},
  series       = {Acta Ophthalmologica},
  title        = {Validation, test-retest reliability and norm scores for the Dutch Catquest-9SF},
  url          = {http://dx.doi.org/10.1111/aos.13287},
  volume       = {95},
  year         = {2017},
}