Disease activity and functional disability in rheumatoid arthritis patients

The main objective of this study was to assess correlations between disease activity and functional disability (as a part of health related quality of life), in hospitalized patients with active RA. Of 169 patients hospitalized in 2001 and 2002 in Rheumatology Department, 87% were women. The following variables were assessed at one time point: 28-joint count, ESR, CRP, morning stiffness, RADAI (Rheumatoid Arthritis Disease Activity Index), pain and global health (VAS). Disease activity was expressed as the Disease Activity Score (DAS28). Physical disability was estimated by the Health Assessment Questionnaire (HAQ). Data were analyzed by Speamans’s coefficient of correlation and multiple logistic regressions. The median values for disease duration, DAS 28, HAQ, age in the study group were: 6 years, 5.43, 1.88, 56 years respectively, which suggest rather young population with high disease activity. Functional disability (HAQ) was significantly positively correlated with DAS 28 (r=0.44; p<0.0001), general health (r=0.42; p<0.0001), disease activity during the last 6 months (r=0.41; p<0.0001) and in the day of assessment (r=0.37; p<0.0001), morning stiffness (r=0.40; p<0.0001), pain measured by VAS (r=0.33; p<0.0001) and CRP (r=0.32; p<0.0001). Disease activity score (DAS28) was also significantly positively correlated with all mention above variables, especially with pain (r=0.44; p<0.0001). The best prediction of high disability (HAQ >2.25) was achieved by CRP concentration and degree of radiological joint destruction in patients < 55 years, and by DAS 28 and VAS (pain) in patients <55 years. For the prediction of high physical disability among patients under 55 years crucial role seems to play CRP (OR=1.04 for CRP 10 – 40 mg/dl vs. CRP ≤10 mg/dl). In the patients over 55 years, the disease activity score (DAS 28) greater than 4.5 and the pain greater than 70 mm in visual analogue scale (VAS) increase significantly the risk of the high disability level (HAQ >2.25). Odds ratios for mentioned above values were: 1.83 (for DAS 28 >4.5 vs. DAS 28 ≤4.5), 1.03 (for VAS >70 mm vs. VAS ≤70 mm). Physical disability in hospitalized RA patients is significantly positively correlated with disease activity. There is a need to pay attention, in the prevention of disability and health related quality of life improvement, to CRP concentration range 10 – 40 mg/dl in patients under 55 years old, and to DAS 28 >4.5 and/or VAS (pain) >70 mm in patients over 55 years old. Visual analogue scale for the pain seems to be simply test for determination of the disability in older RA patients.