Instructions: For each activity, choose the response that best describes the patient's usual abilities over the past week. Leave an activity blank if it does not apply. Under each category, tick any aid or device usually used, or help usually needed from another person. A score is calculated once at least 6 of the 8 categories have an answer.
📋 What This Calculator Does
The HAQ-DI measures functional disability across eight domains of daily living: dressing and grooming, arising, eating, walking, hygiene, reach, grip, and activities. Each domain contains two or three specific questions rated 0 (no difficulty), 1 (some difficulty), 2 (much difficulty), or 3 (unable to do). The domain score is the maximum (hardest) question in that domain. The overall HAQ-DI is the average of the eight domain scores, ranging from 0 to 3.
An important scoring adjustment: if the patient usually uses an aid or device for a category (for example a cane, a raised toilet seat, or a jar opener), or usually needs help from another person, a category score of 0 or 1 is raised to 2. Scores of 2 or 3 are not changed. This is the standard HAQ-DI. The alternative HAQ-DI ignores aids, devices, and help, and is shown underneath the main result.
The overall score is the sum of the category scores divided by the number of categories answered. It is not calculated when fewer than 6 of the 8 categories have an answer. The scale has 25 possible values from 0 to 3 in steps of 0.125.
📊 Interpreting the Score
| HAQ-DI Score | General interpretation |
|---|
| 0 to 1 | Mild to moderate difficulty |
| 1 to 2 | Moderate to severe disability |
| 2 to 3 | Severe to very severe disability |
These ranges are the general guide given by the HAQ developers (Bruce and Fries, 2003). The source gives no exact rule for scores of exactly 1 or 2; this calculator places 1.0 in the first range and 2.0 in the second. A score of 0 with no aids or help is shown as no reported difficulty. For change over time, a minimal clinically important difference of 0.22 is often used in RA; the developers note that some investigators consider about 0.10 clinically important.
💡 Pearls and Pitfalls
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Disability predicts outcomes. HAQ-DI scores have repeatedly been correlated with mortality, progression of aging, and health care use, so the score carries prognostic as well as functional information.
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HAQ-DI is not part of the remission criteria. ACR/EULAR Boolean remission uses tender and swollen joint counts, CRP, and patient global assessment. A HAQ-DI of 0.5 or less is the functional outcome that the remission definitions were validated against, not a criterion. See the
Boolean remission calculator.
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Forgetting aids, devices, and help. A patient who answers "no difficulty" while using a cane, or who needs another person to help with dressing, has a category score of 2, not 0. Skipping these boxes underestimates disability.
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HAQ-DI can plateau even with good disease control. Patients with longstanding RA who have accumulated structural joint damage may have persistently elevated HAQ-DI even when inflammatory disease is well controlled. This "damage-driven" HAQ elevation does not necessarily indicate active inflammation requiring treatment escalation.
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Age, comorbidities, and obesity all independently raise HAQ-DI. An older patient with knee osteoarthritis, obesity, and RA may score in the moderate or severe range regardless of RA activity. Always interpret in the full clinical context.
🔬 Evidence
The HAQ was originally developed by Fries, Spitz, and colleagues at Stanford and published in Arthritis and Rheumatism in 1980. The Disability Index subscale (HAQ-DI) became the standard functional outcome measure in rheumatology and has been used in virtually every pivotal RA clinical trial over the past 40 years. It has been translated and validated in over 60 languages.
A minimal clinically important difference of 0.22 was reported by Wells and colleagues from the patient's perspective; the HAQ developers note that others regard about 0.10 as clinically important. Long-term cohort data, including the work of Pincus and colleagues, showed that questionnaire measures of function predict mortality in RA. Scoring on this page follows the Stanford scoring conventions: highest item per category, aids, devices, and help raising 0 or 1 to 2, and at least 6 categories answered.
View References▾
1
Fries JF, Spitz PW, Kraines RG, Holman HR. Measurement of patient outcome in arthritis. Arthritis Rheum. 1980;23(2):137-145. Original HAQ development paper, now one of the most cited in rheumatology.
2
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. Comprehensive review of HAQ development, variants, and validation across diseases.
3
Wells GA, Tugwell P, Kraag GR, et al. Minimum important difference between patients with rheumatoid arthritis: the patient's perspective. J Rheumatol. 1993;20(3):557-560. Establishes the MCID of 0.22 for HAQ-DI in RA.
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Pincus T, Brooks RH, Callahan LF. Prediction of long-term mortality in patients with rheumatoid arthritis according to simple questionnaire and joint count measures. Ann Intern Med. 1994;120(1):26-34. Long-term mortality prediction from questionnaire and joint count measures in RA.
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Bruce B, Fries JF. The Stanford Health Assessment Questionnaire: dimensions and practical applications. Health Qual Life Outcomes. 2003;1:20. doi:
10.1186/1477-7525-1-20. Source of the scoring method, the 6-category minimum, and the interpretation ranges.
6
Stanford University School of Medicine, Division of Immunology and Rheumatology. The Health Assessment Questionnaire: scoring conventions for the Disability Index (IMACS Form 04a). Source of the assignment of aids and devices to categories.