HAQ-DI or Health Assessment Questionnaire without Didability Index [1] is an index measuring the quality of life related to health, derived from the longer HAQ. HAQ dates back to the 1980's. It is a general index. In the context of RheumaKit, this index considers how arthritis has an impact on everyday life. The questionnaire is designed to be completed by the patient himself, without the help of a doctor.

HAQ has been conducted by the Stanford Arthritis, Rheumatism, and Aging Medical Information System (ARAMIS) more than 200,000 times in routine and research contexts, and is also recommended by the American College of Rheumatology (ACR) to measure physical functionality in studies about rheumatoid arthritis [2], [3].

The value of the HAQ-DI index can be interpreted in terms of three categories:

• from 0 to 1: mild difficulties to moderate disability,
• from 1 to 2: disability moderate to severe,
• from 2 to 3: severe to very severe disability.

The mean score reported in osteoarthritis studies is 0.8 and 1.2 in rheumatoid arthritis studies. It is 0.49 in the overall population.