To determine the extent to which clinical variables and changes in clinical variables explain depression and depression changes in patients with rheumatoid arthritis (RA).
713 patients with RA attending an outpatient rheumatology clinic were studied at their 2 most recent clinic visits as part of their ordinary rheumatic disease care. Six demographic variables and 7 clinical variables were assessed including the Arthritis Impact Measurement Scale depression score, Stanford Health Assessment Questionnaire Functional Disability Index (HAQ-DI), visual analog scale (VAS) pain scales, joint count, grip strength, am stiffness, and erythrocyte sedimentation rate. Change scores representing the difference between the scores at the last and the next to last visit were calculated for all clinical variables.
About 20% of the variance in depression change scores was explained by changes in clinical variables. The amount of variance explained appeared to be inversely related to the time between visits. Thirty-four percent of the variance in current levels of depression scores was explained by current clinical and demographic variables. The most important predictors of depression score and depression change were VAS Pain and HAQ-DI. At the last clinic visit between 11 and 16% of the depression score was explained by changes in depression scores since the previous clinic visit.
Clinical changes explain 20% of depressive changes between visits, while 34% of current depression scores are explained by current clinical status. Changes in pain and HAQ-DI predict changes in depression.