Objectives: National Institute for Health and Clinical Excellence (NICE) guidelines for anti-tumour necrosis factor (TNF) in rheumatoid arthritis (RA) state that two pre-assessments of Disease Activity Score (DAS28) should be performed a month apart. We performed a retrospective audit of data from six centres to determine the stability of DAS28 between assessments, and the proportion of patients still satisfying eligibility criteria at baseline.
Methods: All RA patients assessed for anti-TNF from six centres had their pre-assessment DAS28 (DAS-1) compared with their baseline DAS28 (DAS0) using paired t-tests, and a similar analysis for the components of the DAS28. Patients who were no longer eligible for anti-TNF at DAS0 were noted.
Results: Six hundred and seventy-nine RA patients showed no significant change in the DAS28, with a mean DAS-1 of 6.74 and DAS0 of 6.73. (P = 0.86). Of the patients, 97.2% fulfilled the UK eligibility criteria at DAS0. Comparison of the individual components of the DAS28 between the two pre-assessment dates showed that there was no significant difference between either the numbers of swollen joints or the erythrocyte sedimentation rate (ESR), but there was a significant increase in the numbers of tender joints of 1.41 (P < 0.001) and in the visual analogue scale (VAS) of 4.22 (P < 0.001).
Discussion: The overwhelming majority of patients who fulfil eligibility criteria for anti-TNF drugs 1 month prior to baseline also fulfil the criteria at baseline. There is no significant change in the DAS28 over the month waiting to go onto anti-TNF therapy. A single assessment of the DAS28 would suffice to enable patients to go on to anti-TNF treatment.