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K.K. O'Brien1,2,3, M. Dzingina4, W. Gao4, E. Namisango4, R. Harding4, A.M. Davis5,1,2,3
1University of Toronto, Department of Physical Therapy, Toronto, Canada, 2University of Toronto, Institute of Health Policy, Management and Evaluation (IHPME), Toronto, Canada, 3University of Toronto, Rehabilitation Sciences Institute (RSI), Toronto, Canada, 4King's College London, Cicely Saunders Institute of Palliative Care, Policy & Rehabilitation, London, United Kingdom, 5University Health Network, Toronto, Canada
Background: The HIV Disability Questionnaire (HDQ) is a patient-reported outcome measure (PROM) developed to measure the presence, severity, and episodic nature of disability among adults aging with HIV. The 69-item multi-dimensional HDQ is comprised of six domains that include:
i) physical,
ii) cognitive,
iii) mental-emotional health symptoms and impairments,
iv) difficulties carrying out day-to-day activities,
v) uncertainty and worrying about the future, and
vi) challenges to social inclusion.
The HDQ is validated for use with adults aging with HIV in Canada, United States, Ireland and United Kingdom. However, the HDQ has had little uptake in clinical practice due to concerns of questionnaire length and time constraints of use in busy clinical and community-based settings.
i) physical,
ii) cognitive,
iii) mental-emotional health symptoms and impairments,
iv) difficulties carrying out day-to-day activities,
v) uncertainty and worrying about the future, and
vi) challenges to social inclusion.
The HDQ is validated for use with adults aging with HIV in Canada, United States, Ireland and United Kingdom. However, the HDQ has had little uptake in clinical practice due to concerns of questionnaire length and time constraints of use in busy clinical and community-based settings.
Purpose: Our aim was to develop a Short-Form HIV Disability Questionnaire (SF-HDQ) to facilitate use in clinical practice with adults aging with HIV.
Methods: We used Rasch analysis to inform item reduction using an existing dataset of adults living with HIV in Canada (n=941) and Ireland (n=96) (n=1037); 427 (41%) of which were ≥50 years of age. Our analytic approach evaluated overall model and item-specific fit. We evaluated model fit with coefficient alpha and Person Separation Indices (PSIs) (≥0.70 acceptable). Individual items were evaluated for item threshold ordering, fit residuals, differential item functioning (DIF) and unidimensionality. For item threshold ordering, we examined item characteristic curves and threshold maps. If clinically meaningful, we merged response options of items with disordered thresholds to obtain ordered thresholds. Items with fit residuals >+/-2.5 and statistically significant Bonferroni-adjustment were removed. For DIF, we considered removing items with response patterns that varied according to country, age group, and gender with >1.0 logit difference. We defined unidimensionality of subscales as <5% of independent t-tests comparing possible patterns in residuals as significant.
Results: We removed 34 items, resulting in a 35-item SF-HDQ with domain structure: physical (20 items reduced to 10); cognitive (3 items; none removed); mental-emotional (11 items to 5); uncertainty (14 items to 5); difficulties with day-to-day activities (9 items to 5) and challenges to social inclusion (12 items to 7). Overall model fit: Coefficient alphas and PSIs ranged from 0.78 (cognitive) and 0.69 (day-to-day activities) to 0.85 and 0.79 (physical and mental-emotional), respectively. Three items were rescored to achieve ordered thresholds (1 item in physical; 2 items in social). All subscales demonstrated unidimensionality. Three items with DIF for country in the social domain were retained because of their clinical importance.
Conclusion(s): The 35-item SF-HDQ offers a brief yet comprehensive disability patient-reported outcome measure for use in clinical practice with adults aging with HIV.
Implications: The SF-HDQ is the first known HIV-specific measure of episodic disability for adults aging with HIV. PROMs of disability are important in physiotherapy practice for describing disability, facilitating goal setting, and identifying timely and appropriate interventions, and referrals to services. Physiotherapists can use the SF-HDQ as a way to measure the presence, severity and episodic nature of disability. Next steps involve assessing the utility of the SF-HDQ and its measurement properties in clinical and community-based settings with adults living with HIV.
Funding, acknowledgements: This research was funded by a Fellowship from the British Academy for Humanities and Social Sciences.
Keywords: HIV/AIDS, Disability, measurement
Topic: Oncology, HIV & palliative care
Did this work require ethics approval? Yes
Institution: University of Toronto
Committee: HIV Research Ethics Board
Ethics number: REB Protocol File #38152
All authors, affiliations and abstracts have been published as submitted.
