HAQ Disability Index (HAQ-DI) Calculator
The Health Assessment Questionnaire Disability Index (HAQ-DI) is a validated patient-reported outcome measure that assesses functional disability across eight domains of daily living: dressing, arising, eating, walking, hygiene, reach, grip, and activities. It is widely used in rheumatoid arthritis and other rheumatic diseases.
About
The HAQ was developed by Dr. James Fries and colleagues at Stanford University in 1980 and has become the most widely used functional status measure in rheumatology. The HAQ-DI assesses 20 questions across 8 domains: dressing/grooming (2 items), arising (2 items), eating (3 items), walking (2 items), hygiene (3 items), reach (2 items), grip (3 items), and activities (3 items). Each domain is scored 0 (without any difficulty) to 3 (unable to do). The total HAQ-DI score is the average of the 8 domain scores, ranging from 0 (no disability) to 3 (severe disability).
Formula
HAQ-DI = (Dressing + Arising + Eating + Walking + Hygiene + Reach + Grip + Activities) / 8
The HAQ-DI score is calculated by averaging the scores from 8 functional domains. Each domain is scored 0-3: 0 = without any difficulty, 1 = with some difficulty, 2 = with much difficulty, 3 = unable to do. Domain scores are adjusted upward if the patient requires aids, devices, or assistance from another person for that domain (minimum score 2 if aids/devices used). The final score ranges from 0 (no disability) to 3 (severe disability).
Score Interpretation
The HAQ-DI is the most widely used functional status measure in rheumatology and is predictive of long-term outcomes including work disability, joint replacement surgery, and mortality in RA. A HAQ-DI score >1 is associated with significant functional limitation and increased healthcare utilization. The minimal clinically important difference (MCID) for HAQ-DI is 0.22-0.25. The HAQ-DI is the primary functional endpoint in most RA clinical trials and is recommended by OMERACT and ACR for core outcome measurement.
No Disability — 0–0
HAQ-DI 0. Able to perform all daily activities without any difficulty.
Management: Continue current management. Maintain exercise program. Monitor functional status annually or with clinical change.
Mild Disability — 0.01–1
HAQ-DI >0-1. Some difficulty with daily activities but maintains independence.
Management: Assess for occupational therapy. Consider assistive devices (jar openers, long-handled tools). Maintain exercise and physical therapy. Monitor every 3-6 months.
Moderate Disability — 1.01–2
HAQ-DI >1-2. Significant functional limitation requiring assistance with some activities.
Management: Refer to occupational therapy and physiatry. Assess for home modifications. Escalate disease-modifying therapy. Evaluate for joint replacement if advanced arthritis.
Severe Disability — 2.01–3
HAQ-DI >2-3. Major functional limitation requiring assistance with most daily activities.
Management: Comprehensive multidisciplinary rehabilitation. Assess for joint replacement surgery. Evaluate social support and caregiver needs. Consider disability services and home health care.
Reference Ranges
| Population | Normal Range | Notes |
|---|---|---|
| Adults with rheumatic diseases | 0-3 (lower = better function) | 0: No disability, >0-1: Mild, >1-2: Moderate, >2-3: Severe |
Dr. Mahmoud El-Sayed
Dr. Mahmoud El-Sayed is a consultant rheumatologist with expertise in functional outcome assessment, inflammatory arthritis, and rehabilitation medicine.
View medical review board & editorial policy →Example Calculation
A 55-year-old woman with RA: Dressing=1, Arising=2, Eating=0, Walking=1, Hygiene=2, Reach=1, Grip=2, Activities=2. HAQ-DI = (1+2+0+1+2+1+2+2)/8 = 11/8 = 1.38. Moderate disability. Recommendation: Escalate DMARD, refer to occupational therapy.
Related Conditions
Related Medications
Common Mistakes
Not adjusting domain scores upward when the patient uses aids or devices
According to the standard HAQ scoring, if a patient uses aids, devices, or requires assistance from another person for a domain, the minimum score for that domain should be 2 (with much difficulty), even if the patient reports less difficulty. This adjustment ensures accurate representation of true functional status.
Using HAQ-DI alone without assessing disease activity (DAS28)
HAQ-DI measures functional disability, which is influenced by both disease activity and structural damage. It should be interpreted alongside disease activity measures like DAS28 to differentiate active inflammation from permanent joint damage as a cause of disability.
Frequently Asked Questions
What is the minimal clinically important difference (MCID) for HAQ-DI?
Can HAQ-DI distinguish between disability from active inflammation vs permanent joint damage?
References
- Fries JF, Spitz P, Kraines RG, Holman HR. Measurement of patient outcome in arthritis. Arthritis Rheum. 1980;23(2):137-145. PubMed
- Bruce B, Fries JF. The Stanford Health Assessment Questionnaire: a review of its history, issues, progress, and documentation. J Rheumatol. 2003;30(1):167-178. PubMed
- Anderson J, Sayles HR, Curtis JR, et al. Converting modified Health Assessment Questionnaire (HAQ) scores: converting between the HAQ-DI and the MDHAQ. J Rheumatol. 2012;39(8):1675-1679.