OP0096 LONGITUDINAL ASSESSMENT OF PAIN IN RA: MCID, PREDICTORS AND THE EFFECT OF ANTI-TNF THERAPY
F. Wolfe, K. Michaud

Wolfe and Michaud note that pain in RA patients has not been as thoroughly investigated as function in RA clinical trials. The purpose of this abstract was to more accurately define parameters for pain, its predictors, and the impact of anti-TNF therapy.

19,479 patients were studied over a six year period totaling 96,675 semiannual observations (mean 5/patient). The VAS pain and the SF-36 bodily pain scales were used to assess pain. The EuroQol assessed quality of life and the minimally clinically important difference (MCID) was assessed by regression.

Results: The VAS pain scale was found to correlate better with clinical variables and QOL and was therefore used for subsequent analyses. The mean pain score was 3.9 (SD 2.8). Patient satisfaction suggested pain scores could be categorized in the following way; ~1.4-very mild, ~3.0-mild, ~4.3-moderate, ~5.3-severe, and ~6.9-very severe. From HAQ and utility variables analysis, the MCID for pain was approximated at 0.5 units. Pain was found to increase very little with duration of RA, 0.017 (CI 0.14-0.19) units per year and decreased with age, 0.01 (CI 0.01- 1.01) units per year.

Pain levels were increased in women (0.31 (CI 0.23-0.39)), those not completing compulsory education (1.64 (CI 1.38-21.90)), and in ethnic minorities (0.72 (CI 0.61-0.83)). Levels were reduced in those with university education (0.79 (CI 0.63- 0.89)). Anti-TNF therapy (infliximab and etanercept) reduced pain by .59 to .73 units. No statistical differences were noted between the two agents, with or without combination methotrexate.

Conclusion: Anti-TNF therapy lowered pain levels in this 6-year observational study. Pain scores could be categorized and suggesting a score greater than 3 represented an unsatisfactory outcome. The MCID for pain is 0.5 units.

Editorial Comments: Because of its subjective nature, physicians often are reluctant to use pain as a measure of disease activity in RA. Pain may also be the result of non-inflammatory aspects of RA such as fixed joint deformities, fibromyalgia, etc. This study has also pointed to ethnic, educational and gender differences in the reporting of pain. However, this study demonstrates the value of pain assessments in RA if collected by VAS in a longitudinal manner.

All information contained within the Johns Hopkins Arthritis Center website is intended for educational purposes only. Physicians and other health care professionals are encouraged to consult other sources and confirm the information contained within this site. Consumers should never disregard medical advice or delay in seeking it because of something they may have read on this website.