Pain intensity in patients with fibromyalgia and rheumatoid arthritis.

Three times daily continuously during a three-week inpatient rehabilitation course a visual analogue scale (VAS) was used in the assessment of pain intensity in 20 female patients with primary fibromyalgia (PF) and 20 female patients with rheumatoid arthritis (RA). The pain intensity in PF patients was constantly twice as high as in RA patients. The effect of the rehabilitation course on pain intensity, as assessed by linear regression analysis, was significantly higher in RA than in PF (p < 0.001). In comparison of the first and the last two days, the pain intensity decreased significantly (P < 0.01) in RA, but not in PF. The patients with PF were more depressive than the RA patients, but a positive correlation between depression score and pain intensity was found only in RA patients. Depression was not able to explain the high pain intensity in PF patients. Continuous monitoring of pain by VAS seems to be a useful tool for assessing changes in pain intensity in patients with rheumatic disorders.