Background In recent years, comprehensive disease control (CDC) or comprehensive disease remission (CDR) is being new target of rheumatoid arthritis (RA) treatment. CDR is defined that all of three indices, 28-joint disease activity score (DAS28) less than 2.3 with C-reactive protein (CPR), yearly progress of Sharp/van der Heijde score (dSHS) within 0.5, and Health Assessment Questionnaire Disability Index (HAQ-DI) less than 0.5, are evaluated as remission. Several reports have commented that it is important to control disease activity tightly, in order to achieve CDR. However, how tight is enough to achieve is still unclear.
Objectives This study is designed to clarify comparable level of DAS28 in order to achieve long-lasting CDR.
Methods 421 RA patients who have been treated consecutively for more than three years, were recruited for this study. Treatment term was divided by one year's period. Patients average DAS28, dSHS, and HAQ-DI were calculated and evaluated as remission when each of indices matched as remission, while all of the three matched remission, CDR was evaluated as achieved. Probability for remission of each of the three and CDR from one year's period to the next is calculated. Probability for remission of the four indices from first year to the year after fourth was also evaluated. Sensitivity and specificity were also evaluated in the same manner.
Average DAS28 in the first year period was divided according to level for 0.1 on scale, and sensitivity and specificity of CDR in the year after fourth was evaluated for each level. Patient's average pain score measured with visual analogue scale (PS-VAS) was also calculated according to treatment year period. PS-VAS was divided by 10mm, and sensitivity and specificity of CDR in the year after fourth was evaluated for each level.
Results Probability ratio for each indices were approximately 75% for DAS28, 75% for dSHS which had not changed as years passes, while 75% to 70% as years passes as gradually decreased for HAQ-DI, and 55% to 48% for CDR.
Sensitivity and specificity demonstrated more than 90% for both probabilities in every treatment year term.
CDR achievement ratio demonstrated that sensitivity gradually decreased as DAS28 increased, while specificity increased as increased. Same tendency demonstrated for PS-VAS. When DAS28 was 1.1, sensitivity demonstrated 10%, and specificity demonstrated 50%. When DAS28 was within 1.6, sensitivity kept more than 70%, however when DAS28 was 1.8, sensitivity and specificity had crossed at approximately 63% (Figure1). When PS-VAS was within 10mm, sensitivity demonstrated 80%, and specificity demonstrated 50%. When PS-VAS raised 20mm, sensitivity and specificity had crossed at approximately 58%.
Conclusions These results suggest that initial tight disease activity control is most important in order to achieve long lasting CDR. DAS28 is controlled within 1.6 in the first year, CDR is guaranteed more than 70%. PS-VAS can perform as supplemental parameter, whereas PS-VAS is kept within 10mm, probability of CDR is maintained 80%.
Disclosure of Interest None declared
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