Determinants of Discordance Between Criteria for Inactive Disease and Low Disease Activity in Juvenile Idiopathic Arthritis

Discordant Perception of Disease Activity Between Providers and Adolescents with Systemic Lupus Erythematosus: A Cohort Study

Discordance in perception of disease activity between adolescent patients with lupus and their providers may influence disease outcomes. We found that patients endorsed higher perceptions of disease activity than providers. Discordance was present at all levels of disease activity, particularly in patients with high activity, nephritis, and/or taking corticosteroids or mycophenolate mofetil.

Disease activity trajectories from childhood to adulthood in the population-based Nordic juvenile idiopathic arthritis cohort

OBJECTIVES

To identify long-term disease activity trajectories from childhood to adulthood by using the clinical Juvenile Arthritis Disease Activity Score (cJADAS10) in juvenile idiopathic arthritis (JIA). Second, to evaluate the contribution of the cJADAS10 components and explore characteristics associated with active disease at the 18-year follow-up.

METHODS

Patients with onset of JIA in 1997-2000 were followed for 18 years in the population-based Nordic JIA cohort. We used a discrete mixture model for longitudinal clustering of the cJADAS10 and its components. We assessed factors potentially associated with higher scores on the patient's global assessment of well-being (PaGA) by hierarchical clustering and correlation analysis.

RESULTS

Four disease activity trajectories were identified based on the cJADAS10 components among 427 patients. In trajectory-group 2, the PaGA and the physician's global assessment of disease activity (PhGA) increased significantly during the course, but not the active joint count. The increase in the PaGA was significantly higher than the increases in the PhGA and the active joint count (p<0.0001). A similar pattern was found among all the patients with active disease in the total cohort. Patients with higher PaGA scores had unfavourable scores on several other patient-reported outcomes.

CONCLUSIONS

We have identified groups of patients based on long-term disease activity trajectories. In our study the PaGA was the most important driver of disease activity into adulthood assessed by cJADAS10. We need to better understand how our patients interpret global well-being and implement strategies to achieve inactive disease perceived both by the patient and the physician.

Researchers in rheumatology should avoid categorization of continuous predictor variables

BACKGROUND

Rheumatology researchers often categorize continuous predictor variables. We aimed to show how this practice may alter results from observational studies in rheumatology.

METHODS

We conducted and compared the results of two analyses of the association between our predictor variable (percentage change in body mass index [BMI] from baseline to four years) and two outcome variable domains of structure and pain in knee and hip osteoarthritis. These two outcome variable domains covered 26 different outcomes for knee and hip combined. In the first analysis (categorical analysis), percentage change in BMI was categorized as ≥ 5% decrease in BMI, < 5% change in BMI, and ≥ 5% increase in BMI, while in the second analysis (continuous analysis), it was left as a continuous variable. In both analyses (categorical and continuous), we used generalized estimating equations with a logistic link function to investigate the association between the percentage change in BMI and the outcomes.

RESULTS

For eight of the 26 investigated outcomes (31%), the results from the categorical analyses were different from the results from the continuous analyses. These differences were of three types: 1) for six of these eight outcomes, while the continuous analyses revealed associations in both directions (i.e., a decrease in BMI had one effect, while an increase in BMI had the opposite effect), the categorical analyses showed associations only in one direction of BMI change, not both; 2) for another one of these eight outcomes, the categorical analyses suggested an association with change in BMI, while this association was not shown in the continuous analyses (this is potentially a false positive association); 3) for the last of the eight outcomes, the continuous analyses suggested an association of change in BMI, while this association was not shown in the categorical analyses (this is potentially a false negative association).

CONCLUSIONS

Categorization of continuous predictor variables alters the results of analyses and could lead to different conclusions; therefore, researchers in rheumatology should avoid it.

Drivers of non-zero physician global scores during periods of inactive disease in juvenile idiopathic arthritis

OBJECTIVE

To investigate the frequency in which the physician provides a global assessment of disease activity (PhGA) >0 and an active joint count (AJC)=0 in children with juvenile idiopathic arthritis (JIA) and search for determinants of divergence between the two measures.

METHODS

Data were extracted from a multinational cross-sectional dataset of 9966 patients who had JIA by International League of Associations for Rheumatology criteria, were recruited between 2011 and 2016, and had both PhGA and AJC recorded by the caring paediatric rheumatologist at the study visit. Determinants of discordance between PhGA>0 and AJC=0 were searched for by multivariable logistic regression and dominance analyses.

RESULTS

The PhGA was scored >0 in 1647 (32.3%) of 5103 patients who had an AJC of 0. Independent associations with discordant assessment were identified for tender or restricted joint count >0, history of enthesitis, presence of active uveitis or systemic features, enthesitis-related or systemic arthritis, increased acute phase reactants, pain visual analogue scale (VAS)>0, and impaired physical or psychosocial well-being. In dominance analysis, tender joint count accounted for 35.43% of PhGA variance, followed by pain VAS>0 (17.72%), restricted joint count >0 (16.14%) and physical health score >0 (11.42%).

CONCLUSION

We found that many paediatric rheumatologists did not mark a score of 0 for patients who they found not to have active joints. The presence of pain in joints not meeting the definition of active joint used in JIA was the main determinant of this phenomenon.