Background Since usage of biologic agents, treatment strategy of Rheumatoid Arthritis (RA) is now being a new target. In T2T principle, our first goal to achieve is clinical remission. Biologic agents are strong tool for the target. For the evaluation of disease activity, some indices such as SDAI, CDAI and Boolean are proposed. And some of biomarkers such as ESR, CRP are proposed and put to practice as a supportive tool for evaluation.
Objectives We have investigated relationship between MMP-3 and clinical indices, such as SDAI, CDAI, Boolean, DAS28 and each component of these indices in order to clarify if MMP-3 could be supportive biomarker for evaluation of treatment effectiveness.
Methods 968 RA patients who have attended to our institute were picked up for this study. The patients had been taken interview and calculated SDAI, DAS28, HAQ, and measured CRP, ESR, and MMP-3 every 3 months. The relationship between DAS28 and MMP-3, and SDAI and MMP-3 were evaluated statistically. Average MMP-3 at measured time when SDAI remission achieved and not achieved were also compared statistically. Linear regression among SJC, TJC, PtGA, PhGA, and CRP on MMP-3 was evaluated statistically.
Patients who have been treated with biologics were also investigated. Their DAS28, SDAI and MMP-3 were measured every 3 months, and the relationship between DAS28 and MMP-3, and between SDAI and MMP-3 were also evaluated statistically. For the patients who were treated with biologic agents, MMP-3 measurement is arranged. Because normal range of MMP-3 is different by gender, MMP-3 improvement ratio (MIR) was calculated. That is MMP-3 value divided by what of last MMP-3 before biologics started. The relationship between DAS28 improvement (DAS-I), what is calculated as difference from the last DAS28 value before biologics started, and MIR and SDAI improvement value compared to last time before biologics (SDAI-I) and MIR were also evaluated statistically.
Results In 2067 times of calculated DAS28 and MMP-3 and 962 times of SDAI and MMP-3, the relationship between the two demonstrated significantly correlated (p<0.0001). Average MMP-3 value at the time of SDAI remission is significantly smaller than other times (p<0.0001). MMP-3 demonstrated significant linear regression with CRP, TJC, and PtGA (p<0.001). SJC and PhGA demonstrated no significant linear regression with MMP-3. MIR also demonstrated significant small value in SDAI remission than other SDAI status (p<0.0001).
Average MIR in patients with biologics is significantly correlated with DAS-I, and SDAI-I (p<0.0001). In patients who could maintain SDAI remission for more than half year demonstrated significantly smaller average MMP-3 than other patients (p<0.0001).
Conclusions These results show that MMP-3 value closely correlates with disease activity. In treatment of RA, we are taking care of management of inflammation as first priority. MMP-3 can be an applicable marker for inflammation of joint cartilage. And at the same time, MMP-3 improvement reflects treatment effectiveness. In measuring MMP-3 and in comparing MMP-3 value relative to primary value, the effectiveness of treatment protocol can be evaluated. This evaluation method is more useful for biologics treatment to evaluate. We should include MMP-3 for both of evaluation of RA disease activity and of treatment effectiveness.
Disclosure of Interest None Declared
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