Confirmatory factory analysis of the Neck Disability Index in a general problematic neck population indicates a one-factor model

Gabel, Charles Philip, Cuesta-Vargas, Antonio I., Osborne, Jason W., Burkett, Brendan, & Melloh, Markus (2014) Confirmatory factory analysis of the Neck Disability Index in a general problematic neck population indicates a one-factor model. The Spine Journal, 14(8), pp. 1410-1416.

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Abstract

BACKGROUND CONTEXT:

The Neck Disability Index frequently is used to measure outcomes of the neck. The statistical rigor of the Neck Disability Index has been assessed with conflicting outcomes. To date, Confirmatory Factor Analysis of the Neck Disability Index has not been reported for a suitably large population study. Because the Neck Disability Index is not a condition-specific measure of neck function, initial Confirmatory Factor Analysis should consider problematic neck patients as a homogenous group.

PURPOSE:

We sought to analyze the factor structure of the Neck Disability Index through Confirmatory Factor Analysis in a symptomatic, homogeneous, neck population, with respect to pooled populations and gender subgroups.

STUDY DESIGN:

This was a secondary analysis of pooled data.

PATIENT SAMPLE:

A total of 1,278 symptomatic neck patients (67.5% female, median age 41 years), 803 nonspecific and 475 with whiplash-associated disorder.

OUTCOME MEASURES:

The Neck Disability Index was used to measure outcomes.

METHODS:

We analyzed pooled baseline data from six independent studies of patients with neck problems who completed Neck Disability Index questionnaires at baseline. The Confirmatory Factor Analysis was considered in three scenarios: the full sample and separate sexes. Models were compared empirically for best fit.

RESULTS:

Two-factor models have good psychometric properties across both the pooled and sex subgroups. However, according to these analyses, the one-factor solution is preferable from both a statistical perspective and parsimony. The two-factor model was close to significant for the male subgroup (p<.07) where questions separated into constructs of mental function (pain, reading headaches and concentration) and physical function (personal care, lifting, work, driving, sleep, and recreation).

CONCLUSIONS:

The Neck Disability Index demonstrated a one-factor structure when analyzed by Confirmatory Factor Analysis in a pooled, homogenous sample of neck problem patients. However, a two-factor model did approach significance for male subjects where questions separated into constructs of mental and physical function. Further investigations in different conditions, subgroup and sex-specific populations are warranted.

Impact and interest:

7 citations in Scopus
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6 citations in Web of Science®

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ID Code: 85520
Item Type: Journal Article
Refereed: No
DOI: 10.1016/j.spinee.2013.08.026
ISSN: 1878-1632
Divisions: Current > Schools > School of Clinical Sciences
Current > QUT Faculties and Divisions > Faculty of Health
Copyright Owner: Copyright 2014 Elsevier
Deposited On: 02 Sep 2015 01:46
Last Modified: 07 Oct 2015 00:58

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