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Quality of Life Research

, Volume 22, Issue 4, pp 875–884 | Cite as

The Hunter Syndrome-Functional Outcomes for Clinical Understanding Scale (HS-FOCUS) Questionnaire: evaluation of measurement properties

  • Ingela Wiklund
  • Mireia Raluy-Callado
  • Donald E. Stull
  • Yvonne Jangelind
  • David A. H. Whiteman
  • Wen-Hung Chen
Original Paper

Abstract

Purpose

This study was to conduct the psychometric validation of the patient and parent versions of the Hunter Syndrome-Functional Outcomes for Clinical Understanding Scale (HS-FOCUS).

Methods

Data collected in a 53-week placebo-controlled multinational trial were used to evaluate item performance and reliability, validity, and ability to detect change of the six HS-FOCUS function domains.

Results

HS-FOCUS was completed by 49 patients above 12 years old and 84 parents. Floor effects and high average inter-item correlations suggested that some items were less informative or redundant. For both patients and parents, the internal consistency and test–retest reliability met the >0.70 criteria for all domains except for the breathing, sleeping, and schooling/work in patients. Construct validity showed moderate to high correlations with CHAQ, CHQ, and HUI3 in activity-related concepts. Significant differences in domain scores were found in most domains among severity in disability measured by CHAQ DIS. Significant differences in HS-FOCUS change scores were found in patients whose CHAQ DIS score also changed.

Conclusions

Psychometric validation of the HS-FOCUS demonstrates it is a reliable, valid, and responsive instrument that can be applied in clinical trials or disease registries. Findings on the individual item performance suggest some items could be removed without compromising its validity.

Keywords

Hunter syndrome Mucopolysaccharidosis type II Lysosomal storage disease Patient-reported outcomes Hunter Syndrome-Functional Outcomes for Clinical Understanding Scale (HS-FOCUS) 

Abbreviations

6MWT

Six-minute walk test

ANCOVA

Analysis of covariance

ANOVA

Analysis of variance

BP

Bodily Pain

CH

Change in Health

CHAQ

Childhood Health Assessment Questionnaire

CHQ

Childhood Health Questionnaire

CHQ-CF

Child Health Questionnaire-Child Form

CHQ-PF

Child Health Questionnaire-Parent Form

DIS

Disability Index Score

FA

Family Activities

FC

Family Cohesion

FEV

Forced expiratory volume

FIM

Functional Independence Measure

FVC

Forced vital capacity

GAG

Glycosaminoglycans

GBE

Global Behavior

GH

General Health Perceptions

HRQL

Health-related quality of life

HS

Hunter syndrome

HS-FOCUS

Hunter Syndrome-Functional Outcomes for Clinical Understanding Scale

HUI

Health Utilities Index

I2S

Iduronate-2-sulfatase

ICC

Intraclass correlation coefficient

MH

Mental Health

MPS II

Mucopolysaccharidosis type II

PE

Parental Impact–Emotional

PF

Physical Functioning

PODCI

Pediatric Outcomes Data Collection Instrument

PRO

Patient-reported outcome

PT

Parental Impact–Time

RB

Role/Social–Behavioral

RE

Role/Social–Emotional

REB

Role/Social–Emotional and the Role/Social–Behavioral

RP

Role/Social–Physical

SD

Standard deviation

SE

Self Esteem

WHO-ICIDH

World Health Organization International Classification of Impairment, Disability and Handicap

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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Ingela Wiklund
    • 1
  • Mireia Raluy-Callado
    • 1
  • Donald E. Stull
    • 2
  • Yvonne Jangelind
    • 3
  • David A. H. Whiteman
    • 4
  • Wen-Hung Chen
    • 5
  1. 1.United BioSource CorporationLondonUK
  2. 2.RTI Health Solutions, The Pavilion, Towers Business ParkManchesterUK
  3. 3.StockholmSweden
  4. 4.Shire AG, Business Park Terre-BonneEysinsSwitzerland
  5. 5.United BioSource CorporationBethesdaUSA

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