HAQ Disability Index
Also known as: HAQ-DI, Health Assessment Questionnaire, Disability Index
The Health Assessment Questionnaire Disability Index (HAQ-DI) is a 20-item self-report measure of functional disability developed by Fries and colleagues at Stanford University in 1980. Originally designed for rheumatoid arthritis, the HAQ-DI has become the gold-standard functional assessment instrument across diverse rheumatic diseases and chronic conditions.
Key highlights
- Extensively validated across rheumatic diseases with strong correlation to other functional and clinical measures
- Sensitive to change in clinical trials; detects meaningful functional improvement and decline
- Simple, intuitive scoring reflects practical disability relevant to patients' lived experience
- Brief administration time (5 minutes) and self-completion enable use in busy clinical settings
- Strong predictive validity for health outcomes, joint damage progression, and mortality in arthritis
Intuition
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How it works
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When to use it
The HAQ-DI is the preferred instrument for assessing functional outcomes in rheumatic disease trials and clinical practice monitoring. It is appropriate for patients aged 5+ years across all arthropathies (rheumatoid arthritis, systemic lupus erythematosus, osteoarthritis, etc.). The HAQ-DI is less suitable for acute injury or post-surgical assessment; condition-specific functional scales may be preferable in those contexts.
Strengths & limitations
- Extensively validated across rheumatic diseases with strong correlation to other functional and clinical measures
- Sensitive to change in clinical trials; detects meaningful functional improvement and decline
- Simple, intuitive scoring reflects practical disability relevant to patients' lived experience
- Brief administration time (5 minutes) and self-completion enable use in busy clinical settings
- Strong predictive validity for health outcomes, joint damage progression, and mortality in arthritis
- Originally designed for arthritis; extrapolation to non-rheumatic conditions may require validation
- Predominantly assesses physical function; does not capture cognitive or emotional disability
- Ceiling effects in mild disease; limited discrimination among high-functioning patients
- Assistive device/help factors may not apply uniformly across cultural contexts and healthcare systems
Common pitfalls
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Applications
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Frequently asked
What is the significance of the assistive device and help factors in HAQ-DI scoring?
The use of assistive devices or needing help from another person reflects disease severity beyond difficulty rating alone. A patient unable to climb stairs even with a cane (score 3 with device) has greater functional impairment than one with difficulty but independence. This weighting makes HAQ-DI more sensitive to real-world disability.
What does a HAQ-DI score of 0.75 indicate?
A score of 0.75 indicates moderate to moderately severe disability, suggesting the patient has significant limitations in routine activities. Contextually, this reflects meaningful disease burden; improvement to 0.5 or below would represent clinically important response to treatment in arthritis trials.
Can HAQ-DI be used in conditions other than rheumatoid arthritis?
The HAQ-DI has been used in systemic lupus erythematosus, osteoarthritis, and other conditions with varying degrees of validation. When using it outside arthritis, ensure the conceptual basis (physical functional limitation) aligns with your condition and validate thresholds against relevant outcome measures.
How often should HAQ-DI be assessed in clinical monitoring?
In clinical practice, HAQ-DI is typically assessed at baseline and at defined follow-up intervals (e.g., quarterly or semi-annually) aligned with disease activity monitoring. In trials, assessment frequency depends on expected rate of functional change; monthly in intensive interventions, quarterly in typical drug trials.
Sources
- 1.Bruce, B., & Fries, J. F. (1989). The Stanford Health Assessment Questionnaire: a review of its history, issues, progress, and documentation. Journal of Rheumatology, 16(8), 1055–1064.
- 2.Fries, J. F., Spitz, P., Kraines, R. G., & Holman, H. R. (1980). Measurement of patient outcome in arthritis. Arthritis & Rheumatism, 23(2), 137–145.
- 3.Pincus, T., Swearingen, C., & Wolfe, F. (2011). Toward a multidimensional Health Assessment Questionnaire (MDHAQ): assessment of advanced activities of daily living and psychological well-being. Seminars in Arthritis and Rheumatism, 30(2), 10–17.
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Cite this page
ScholarGate. (2026, June 3). HAQ Disability Index. ScholarGate. https://scholargate.app/health-measurement/haq-disability-index