Evaluation of the psychometric properties of the HIV Disability Questionnaire among adults living with HIV in the United Kingdom

Objective To evaluate the psychometric properties of the HIV Disability Questionnaire (HDQ) among adults living with HIV in London, United Kingdom (UK). Methods This is a cross-sectional measurement study. We recruited and administered the self-reported HDQ, seven criterion measures, and a demographic questionnaire with adults living with HIV accessing HIV care. We determined median and interquartile ranges (IQR) for disability presence, severity and episodic scores (range 0-100). We calculated Cronbach’s alpha (α) Kuder-Richardson-20 (KR-20) statistics for disability and episodic scores respectively (internal consistency reliability), smallest detectable change (SDC) for each HDQ severity item and domain (precision), and tested 36 a priori hypotheses assessing correlations between HDQ and criterion scores (construct validity). Results Of N=243 participants, all were male, median age 40 years, 94% currently taking antiretroviral therapy, and 22% living with ≥2 concurrent health conditions. Median HDQ domain scores ranged from 0 (IQR: 0,7) (difficulties with day-to-day activities domain) to 27 (IQR: 14, 41) (uncertainty domain). Cronbach’s alpha for the HDQ severity scale ranged from 0.85 (95% Confidence Interval (CI): 0.80-0.90) in the cognitive domain to 0.93 (95%CI: 0.91-0.94) in the mental-emotional domain. The KR-20 statistic for the HDQ episodic scale ranged from 0.74 (95%CI: 0.66-0.83) in the cognitive domain to 0.91 (95%CI: 0.89-0.94) in the uncertainty domain. SDC ranged from 7.3-15.0 points on the HDQ severity scale for difficulties with day-to-day activities and cognitive symptoms domains, respectively. The majority of the construct validity hypotheses (n=30/36, 83%) were confirmed. Conclusions The HDQ possesses internal consistency reliability and construct validity with varied precision when administered to males living with HIV in London, UK. Clinicians and researchers may use the HDQ to measure the nature and extent of disability experienced by PLHIV in the UK, and to inform HIV service provision to address the health-related challenges among PLHIV.