科研之友
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摘要
AIMS Composite indices for quantifying rheumatoid arthritis (RA) disease activity such as the 28-joint disease activity score (DAS28) are comprised of single parameters ('metrics') in various combinations. Population modelling methods were used to evaluate single metrics for their ability to reflect changes in disease activity with a view to understanding and improving composite indices. METHODS A total of 11 single metrics of RA disease activity (tender and swollen joint counts, acute phase reactants and global health, pain and physical function assessments) were obtained from 203 patients with recent onset RA. Participants received combination disease-modifying anti-rheumatic drugs (DMARDs) according to a treat-to-target approach with a pre-defined protocol for treatment intensification. Models describing each metric's magnitude and variability of change from baseline to a single 'treated' state in the population were developed using NONMEM (R). Measures that displayed uniformly large changes between states across the population were ranked higher in terms of discriminatory capacity. RESULTS Joint counts demonstrated a greater ability to discriminate changes in RA disease activity than others. Correlations between metrics demonstrated that erythrocyte sedimentation rate (ESR) had limited relationships with others for baseline scores and changes in RA disease activity (r generally < 0.2). However it appeared to be important in describing changes for those individuals where ESR levels were initially elevated. CONCLUSION It appears unlikely that a single group of metrics may be suitable to capture disease activity changes across all RA patients and defining the most appropriate metric(s) for individual patients will be an important area of future research. WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Titrating doses of disease modifying anti-rheumatic drugs (DMARDs) according to a patient's current level of disease activity is effective for achieving remission in rheumatoid arthritis (RA). A single or compositemeasure that best reflects response to DMARD therapy (or lack thereof) is yet to be identified. A previous populationmodel of RA disease progression described high within-patient random variability suspected to be due to fluctuations within the modelled composite measure itself. WHAT THIS STUDY ADDS Swollen and tender joint counts, physician's assessment of patient's global health and pain were found to distinguish the effect of DMARD therapy better than acute phase reactants or the patient's assessment of global health. Correlations between RA disease activity metrics demonstrated that acute phase reactants have limited relationships with other metrics in terms of baseline and changes in disease activity. Acute phase reactants may be important descriptors for changes in RA disease activity in those whose levels were elevated initially.
- 出版日期2016-6
