The aim of this study was to determine from patient perspective the most relevant physical functions when estimating the functional disabilities, and to estimate the perceived relative influence of them. Structured telephone interviews were conducted among 143 RA patients. The subjects were asked to name functions and activities in their everyday life, which were affected by RA. After this, they were asked to score each of the named item with a scale from 0 to 100. These were combined with earlier collected data on sociodemographic background and clinical status. Listed activities were grouped to functional disabilities and further categorized according to joints, limbs and body areas. One or more functional disabilities affecting everyday life because of RA was mentioned by 87.4%, altogether 354 mentions. The most commonly mentioned disabilities were walking and opening jars. However, the most commonly mentioned disabilities were not those with highest perceived disabilities. Of the 59 different types of disabilities mentioned, 25 were connected with movements of the shoulder, 30 with elbow, 40 with wrist, and 37 with fingers. Movements of the back were involved in 20 mentioned disabilities, hip and knee both in 8, and ankles in 6. Disabilities related to lower extremity functions were considered most disabling. In conclusion, to describe RA patients' functional disability, the measured functions should be those which the patients themselves consider relevant and causing disability. Furthermore, the studied functional measures ought to be weighted according to the relative influence of each function to the patients.

Objectives: To evaluate the relative importance of the twenty functions assessed by patients to produce the Health Assessment Questionnaire's Disability Index (HAQ-DI).Methods: A systematic sample of 242 rheumatoid arthritis patients was drawn. Altogether 179 subjects returned acceptably filled questionnaire including perceived rheumatoid arthritis status in the 20 functions comprising the HAQ-DI. A separate complementary questionnaire was sent to 80 randomly chosen subjects. They were asked to estimate how important each of the same twenty items were in their everyday life by using the VAS method. Completely answered complementary questionnaires were returned by 66 (88%) of the subsample.Results: The relative importance of the functions assessed varied considerably. Men assessed the highest importance to the ability to walk outdoors on flat ground and women to dressing themselves, getting in and out of bed and washing and drying their body. For both genders the least important function was the ability to take a tub bath. The importance of all other functions except taking a tub bath were positively highly significantly correlated with the importance of each of the other functions. Factor analyses with one factor model showed high loadings on most functions, with the exception of 'Take a tub bath'. The two factor model formed one factor with loadings concentrating slightly more on 'lower extremity' and another on 'upper extremity'.Conclusions: Assessment of RA patients' functional status would benefit from further development of measures by giving relative weights from patients' perspective to those functional abilities which are used for index computations.