Questionnaire-Based Assessment of Physical Disability in COPD

Abstract

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.

Introduction

Chronic Obstructive Pulmonary Disease (COPD) is a major global health challenge, affecting 6 to 10% of the population over the age of 40 and responsible for a considerable socio-economic burden.¹ COPD is a heterogeneous disease characterised by chronic respiratory symptoms due to airway and/or alveoli abnormalities, responsible for persistent and progressive airflow obstruction.² It is frequently associated with comorbidities, including cardiovascular diseases, anxiety and depression, contributing to the disease burden.^3,4 Systemic effects of COPD have been described, including weight loss and nutritional anomalies, as well as skeletal muscle dysfunction and sarcopenia.⁵

COPD is clinically characterised by a progressive limitation of exercise capacity, induced by both static and dynamic hyperinflation,⁶ and additionally impaired by COPD-associated skeletal muscle dysfunction among other potential comorbidities.⁷ Dedicated questionnaires can be used to assess symptoms and exercise capacity in COPD, such as the mMRC (modified Medical Research Council) scale assessing dyspnea, and the CAT (COPD assessment test) assessing respiratory symptoms and activity limitations. A quantitative assessment of exercise limitation requires dynamic testing, including walking distance measurements or incremental exercise testing in a laboratory. Exercise capacity in COPD has been identified as a predictor of prognosis, as it may fall in the year before death.⁸

The Health Assessment Questionnaire-Disability Index (HAQ-DI) is a validated, easy-to-use auto-questionnaire to assess and monitor difficulties in performing the daily living activities (ie, health-related disability) in rheumatologic diseases. It has been applied in rheumatoid arthritis,⁹ systemic sclerosis^10,11 and systemic sclerosis-associated interstitial lung disease.^12,13 HAQ-DI cut-off scores have been initially defined for rheumatologic diseases, with scores 0–1 representing mild to moderate difficulty, 1–2 moderate to severe disability, and 2–3 severe to very severe disability.¹⁴ The relevance and usefulness of HAQ-DI in COPD have not been assessed.

The objective of this pilot study was to assess physical disability in COPD using the HAQ-DI questionnaire. We hypothesised that HAQ-DI scores are altered in COPD and associated with quality-of-life impairment.

Materials and Methods

Patients

COPD patients (GOLD stages 1–4) were recruited prospectively and included in the observational monocentric RINNOPARI study (Recherche et INNOvation en PAthologie Respiratoire Inflammatoire) between 2016 and 2025. The study was approved by the French ethics committee (Comité de Protection des Personnes - Dijon EST I, N°2016-A00242-49) and registered in clinicaltrials.gov (NCT02924818). Each patient signed a written informed consent. The study complies with the Declaration of Helsinki. Patients were included at a stable state (4 weeks or more from the last exacerbation). Patients with asthma, alpha-1-antitrypsin deficiency, cystic fibrosis, bronchiectasis or pulmonary fibrosis, or unable to perform a 6-minute walking test (6MWT), were excluded.

At inclusion, demographic and clinical data, functional (pulmonary function tests including spirometry, plethysmography and DLCO measurements, 6-min walking test, arterial blood gas), laboratory, and thoracic CT-scan results were recorded. COPD was defined by suggestive symptoms (cough, chronic bronchitis, dyspnea on exercise) and postbronchodilator FEV₁/FVC <70%. The severity of COPD was determined by spirometric classification (GOLD 1: FEV₁ ≥ 80% predicted, GOLD 2: 50% ≤ FEV₁ < 80% predicted, GOLD 3: 30% ≤ FEV₁ < 50% predicted, GOLD 4: FEV₁ < 30% predicted) and the 2025 GOLD ABE classification.² CT scans were analysed by two independent investigators (SD, GD) using a visual emphysema quantification.¹⁵ Questionnaires assessing respiratory symptoms (mMRC, Cough And Sputum Assessment Questionnaire (CASA-Q), psychological symptoms (HAD) and quality of life (St George’s Respiratory Questionnaire (SGRQ), European Quality of Life 5 Dimensions (EQ-5D), Short Form 36 Health Survey (SF-36)) were performed. Activity limitation was assessed using the CAT.

The assessment of disability was performed using the validated French version of the HAQ-DI, which evaluates 8 dimensions of daily life activities.¹⁶ Each item was rated on an ordinal scale from 0 (no impairment) to 3 (severely disabled).^14,17 The final score (Disability Index) is calculated by averaging the highest scores of each domain, ranging from 0 to 3.

Statistical Analysis

Statistical analysis was performed using SPSS software (version 28.0.1.0). Normality was assessed using the Shapiro–Wilk test. Quantitative variables with normal distribution were expressed as mean ± standard deviation (SD), and non-normal variables as median [25^th–75^th percentiles]. Qualitative variables are expressed as numbers and percentages. Comparisons between groups were performed using the Chi-square or exact Fisher’s test for qualitative variables and the Mann–Whitney U-test for quantitative variables. Associations between the HAQ score and disease severity markers were assessed using Pearson’s or Spearman correlation coefficients, depending on distribution. Multivariate analyses were performed using linear regression for variables related to phenotypic and burden features with p-values <0.01. A p-value <0.05 was considered significant.

Results

A total of 117 patients were included (Table 1). Briefly, patients were predominantly male (59%) with a mean age of 61.6 ± 8.9 years and a smoking history of 45.2 ± 23.1 pack-years. COPD was severe to very severe for 56.4% of the cases, with a residual volume >150% for 79%, and a mean of 2.6 ± 2.3 exacerbations in the last year; 74.4% described a dyspnea mMRC score ≥2, and 34.2% had a 6-minute walking distance (6MWD) <350 meters.

Table 1.

Population Characteristics

	Subjects
n	117
Age, yrs	61.6 ± 8.9
Men	69 (59.0)
BMI, kg/m2	25.4 ± 6.0
Current smoker	37 (31.6)
Smoking history, pack-year	45.2 ± 23.1
Cardiovascular disease	60 (51.3)
Depression	33 (28.2)
Osteoporosis	5 (4.2)
Treatment
No inhaled treatment	25 (21.4)
LABA or LAMA	7 (6.0)
LABA + LAMA	33 (28.2)
CSI + LABA or CSI + LAMA	19 (16.2)
CSI + LABA + LAMA	33 (28.2)
Long-term oxygen	15 (12.8)
Exacerbation in the previous year	87 (74.4)
Number per patient	2.6 ± 2.3
Hospitalisation	43 (36.8)
Dyspnea mMRC ≥ 2	87 (74.4)
Clinical GOLD 2025 A/B/E	13/33/71
FEV1, % pred	47.7 ± 19.1
FEV1/FVC	47.8 ± 10.7
RV, % pred	213.1 ± 80.1
TLC, % pred	130.9 ± 31.9
DLCO, % pred	45.9 ± 21.6
Spirometric GOLD
GOLD 1-2	51 (43.6)
GOLD 3-4	66 (56.4)
6-minute walking test, n	117
Dyspnea, Borg	5.0 ± 2.4
Distance, m	363 ± 115
Distance < 350m, n	49 (34.2)
CT-scan, n	117
Emphysema, n	101 (86.3)
Emphysema score	8.4 ± 5.1

Note: Data are expressed as a number (percentage) or mean ± standard deviation.

The median value of the HAQ-DI score was 0.38 [0.0–0.75]; 20 patients (17.1%) had an HAQ-DI score ≥1, and 2 patients (1.7%) had an HAQ-DI score ≥2.

HAQ-DI Score is Impaired in Severe COPD and Associated with Phenotypic Features

The HAQ-DI score was associated with the severity of airway obstruction (FEV₁/FVC: p = 0.014, r² −0.226; FEV₁, p = 0.003, r² −0.269), and significantly higher in severe and very severe COPD when compared with mild and moderate COPD (0.25 [0–0.63] in COPD GOLD 1–2 vs 0.50 [0.13–0.75] in COPD GOLD 3–4, p = 0.015). The HAQ-DI scores were not associated with patients’ age or gender (Figures 1 and 2a, b, e).

Figure 1.

HAQ-DI scores distribution in the mild to moderate COPD (GOLD 1–2) and the severe to very severe COPD (GOLD 3–4) groups. The line represents the median value.

Figure 2.

Associations between the HAQ-DI scores and demographic characteristics (a and b); phenotypic features (c–f) and burden-associated scores (g–i). ** p < 0.01; ***p < 0.001.

When assessing the phenotype of COPD patients associated with HAQ-DI impairment, univariate analyses identified that cardiovascular comorbidities (cardiac insufficiency of any cause and/or arterial hypertension) and depression were associated with higher HAQ-DI scores (p = 0.008 and p = 0.041, respectively). HAQ-DI impairment was further associated with COPD clinical features, including dyspnea mMRC score (mMRC < 2: 0.0 [0.0–0.28] vs mMRC ≥ 2: 0.5 [0.25–0.75], p < 0.001), the number of exacerbations in the previous year (p = 0.015, r² 0.261), the history of severe exacerbation requiring hospitalisation (no hospitalisation: 0.31 [0.0–0.63] vs ≥1 hospitalisation: 0.5 [0.13–1.00], p = 0.021), and the clinical GOLD E status (p = 0.001) (Figure 2c). HAQ-DI was not associated with the cough and sputum CASA-Q scores. As expected, HAQ-DI scores were correlated with the COPD-dedicated activity limitation assessment CAT scores (p < 0.001, r² 0.523), SpO2 at rest in ambient air (p = 0.005, r² −0.274), and with the 6MWT results, including dyspnea Borg score (p < 0.001, r² 0.349) and walking distance (p < 0.001, r² −0.463) (Figure 2d, f and Supplemental Table 1).

Multivariate analysis identified that HAQ-DI scores were significantly associated with the CAT scores (p = 0.001, 95%  CI  [0.014; 0.041]) and the 6MWD (p = 0.021, 95%  CI  [−0.002; -0.0002]) (Supplemental Table 1).

HAQ-DI Score is Associated with Disease Burden

Considering the symptom scores related to disease burden, univariate analyses identified that HAQ-DI scores were correlated to quality of life questionnaire results: EQ-5D (p < 0.001, r² −0.594), SF-36 (physical score: p < 0.001, r² −509; mental score: p = 0.001, r² −0.305) and SGRQ p < 0.001, r² 0.664. HAQ-DI scores were further correlated with HAD anxiety and depression scores (p < 0.001, r² 0.037 and p < 0.001, r² 0.548, respectively) (Figure 2g–i and Supplemental Table 1).

Multivariate analysis identified that HAQ-DI was significantly associated with the SGRQ total score (p = 0.017, 95% CI [0.002; 0.016]) and HAD-Depression score (p = 0.008, 95% CI [0.010; 0.063]) (Supplemental Table 1).

The High Functional Disability Phenotype is Associated with COPD Prognosis Markers

We next focused on the subjects with HAQ-DI scores ≥1, defining moderate to severe disability.¹⁸ When compared to the group with HAQ-DI scores <1, the High Functional Disability (HFD) group (HAQ-DI ≥ 1, n = 20) was characterised by more frequent COPD high-risk prognosis factors,^19–22 including 6MWD ≤334m (70.0% vs 32.0%, p = 0.002), BODE index ≥3 (90.0% vs 66.0%, p = 0.033), ≥2 exacerbations in the last year (85.0% vs 34.0%, p < 0.001) and FEV₁<50% (75.0 vs 49.5%, p = 0.031) (Figure 3). In addition, the HFD group exhibited a marked disease burden: CAT score ≥20 in 77.8% (vs 29.1%, p < 0.001), SGRQ score ≥50 in 75.0% (vs 37.8%, p = 0.003), HAD-Anxiety score >7 in 90.0% (vs 40.4%, p < 0.001) and HAD-Depression score >7 in 80.0% (vs 28.7%, p < 0.001) (Figure 3).

Figure 3.

COPD phenotypes depending on the HAQ-DI. The High Functional Disability COPD phenotype (HAQ-DI ≥1 group, black line) is associated with more frequent COPD high-risk prognosis features and severe burden. * p < 0.05; ** p < 0.01; ***p < 0.001.

Discussion

In this prospective study, we identified that the physical disability score HAQ-DI is impaired in severe and very severe COPD, and is associated with respiratory functional features as well as altered quality of life and psychological burden. We defined a High Functional Disability COPD phenotype associated with high-risk prognosis markers and severe disease burden.

COPD is a complex systemic disease where chronic inflammation, tissue remodelling, and comorbidities drive activity limitation.^2,5,14 The severity of COPD is currently defined either by functional results (FEV₁, GOLD 1–4 classification) or by a combination of symptom score and exacerbation events (GOLD ABE).² However, FEV₁ represents a poor predictor of activity limitation.^23,24 The assessment of activity limitation requires dynamic testing (walking distance measurements, incremental exercise testing) that may not be feasible in some COPD patients. In our study, a higher HAQ-DI score was associated with the severity of COPD, as defined both functionally and symptomatically. In addition, the HAQ-DI scores were independently associated with the 6MWD, suggesting that this patient-centred tool could be useful when dynamic testing is not available or feasible.²⁴ The HAQ-DI questionnaire includes items assessing upper limb activities (washing hair, reaching). In COPD with lung distension, arm elevation may cause thoraco-abdominal dyssynchrony and early dyspnea, as accessory muscles are diverted from ventilatory function.^25,26 Although we did not find an association between the HAQ-DI score and residual volume (RV) value in our study, where significant lung distension was very frequent, the HAQ-DI score might capture such a mechanical disability component that lower-limb-focused tests do not.

HAQ-DI was associated in our study with the CAT, SGRQ and HAD-Depression scores. The SGRQ is the gold standard to assess quality of life in patients with chronic respiratory diseases. However, due to its complexity, it is rarely used in routine.²⁷ While the CAT mainly focuses on respiratory symptoms and burden,²⁸ the HAQ-DI assesses physical disability and its impact on daily activities, suggesting that their combined use could provide a holistic assessment of COPD patients. Elevated HAQ-DI scores, easily used in routine, could lead to more complex, burden-specific questionnaires and comorbidities-specific assessment.

Given the distribution of HAQ-DI scores in our study, and the previously described cut-off scores for rheumatologic diseases, we described the HFD-COPD phenotype, defined by HAQ-DI score ≥1, and characterised by frequent high-risk prognosis markers and severe disease burden.^19–22 This HFD-COPD phenotype represented 17.1% of the patients in our study. Previous studies identified that 20% of COPD patients were affected by frailty, a state of increased vulnerability including reduced physiological resilience and heightened susceptibility to external stressors.^29–31 The use of HAQ-DI could enable rapid vulnerability screening and identify COPD patients combining exacerbation risk, psychological distress, and poor prognosis. Those should benefit from dedicated management, including treatment optimisation, pulmonary rehabilitation, and psychological and social support.

Our study has some limitations. The monocentric design of the study represents an important limit. However, patients were prospectively recruited and underwent in-depth phenotypic characterisation, including burden assessment. We exclude subjects unable to perform a 6MWT, representing a potential recruitment bias. Additional investigations regarding body composition/muscle strength would have been interesting to assess sarcopenia’s involvement. Further studies are needed to assess the disease trajectories depending on the HAQ-DI scores.

Conclusion

This study suggests that the HAQ-DI is a simple and relevant tool for assessing physical disability in patients with COPD: higher HAQ-DI scores were associated with greater disease severity, reduced exercise capacity, poorer health-related quality of life, and increased psychological burden. We also identified a High Functional Disability phenotype (HAQ-DI ≥ 1) characterised by multiple markers of poor prognosis and substantial disease burden. These findings support the use of the HAQ-DI as a practical patient-centred instrument that may complement current COPD assessment, particularly when functional exercise testing is unavailable, and help identify patients who could benefit from personalised management such as pulmonary rehabilitation and psychological support. Beyond extending the use of the HAQ-DI to COPD, our results highlight the importance of integrating disability assessment into the multidimensional evaluation of the disease. Larger multicentre longitudinal studies are now needed to validate these findings and determine the prognostic value of the HAQ-DI in COPD.

Funding Statement

The RINNOPARI study received a grant from the University Hospital of Reims, France, and the University of Reims Champagne-Ardenne, France.

Data Sharing Statement

The deidentified data that support the findings of this study are available from the corresponding author upon reasonable request to jmperotin-collard@chu-reims.fr.

Ethics Approval and Informed Consent

The study was approved by the French ethics committee (Comité de Protection des Personnes - Dijon EST I, N°2016-A00242-49) and registered in clinicaltrials.gov (NCT02924818). Each patient signed a written informed consent.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

S Dury reports honoraria for lecturing from Boeringer Ingelheim outside the submitted work. V Dormoy reports support for attending meetings from AstraZeneca outside the submitted work. J Ancel reports support for attending meetings from Roche, Pfizer, Bristol-Myers Squibb, Novartis, AstraZeneca, Takeda, Sanofi and Amgen outside the submitted work. G Deslee reports honoraria for lecturing and advisory board from AstraZeneca, Chiesi, GSK, Sanofi and Menarini outside the submitted work. J.M. Perotin reports honoraria for lecturing from AstraZeneca and Stallergenes-Greer, and support for attending meetings from AstraZeneca, Stallergenes-Greer, ALK and Chiesi outside the submitted work. There are no further conflicting interests to disclose.