Questionnaire-Based Assessment of Physical Disability in COPD.

Purpose: Chronic Obstructive Pulmonary Disease (COPD) is characterized by a progressive limitation of exercise capacity and functional disability, induced by both airway obstruction, skeletal muscle dysfunction and comorbidities, contributing to the disease burden. The Health Assessment Questionnaire - Disability Index (HAQ-DI), a validated tool assessing functional disability in rheumatologic diseases, with higher scores reflecting more severe disability, may be of interest in COPD. This study aimed to assess functional disability in COPD using the HAQ-DI and its association with disease severity and burden. Patients and Methods: Mild to very severe COPD patients were included in the RINNOPARI prospective cohort (NCT02924818). Pulmonary function tests and 6-minute walking test (6MWT) results, HRCT emphysema quantification, and patient-reported outcomes, including mMRC, CAT, SGRQ, EQ-5D and SF-36, were recorded. Functional disability was assessed using the French version of the HAQ-DI. Results: A total of 117 patients were included, with a median HAQ-DI score of 0.38 [0.0-0.75]. HAQ-DI scores were significantly higher in COPD GOLD 3-4 (0.50 [0.13-0.75] vs 0.25 [0-0.63] in COPD GOLD 1-2, p = 0.015). HAQ-DI was associated with cardiovascular and depression comorbidities (p < 0.05), COPD clinical features (number of exacerbations, p = 0.015; mMRC dyspnea score, CAT score and 6MWT distance, all p < 0.001), and COPD burden as assessed by SF-36, SGRQ and HAD anxiety and depression scores, p < 0.001 for all. Multivariate analysis identified the 6MWT distance, CAT, SGRQ, and HAD-Depression scores as independent factors associated with HAQ-DI. We further identified a « High Functional Disability » (HFD) phenotype defined by HAQ-DI ≥ 1 (n = 20), and characterized by COPD poor prognosis markers and severe disease burden. Conclusion: The HAQ-DI is a feasible tool for screening functional disability in COPD. It allowed the identification of a « high-risk, high burden » phenotype, which could benefit from personalised management such as pulmonary rehabilitation and psychological support.