Although psoriatic arthritis activity indices might suggest disease severity, this retrospective study demonstrated that disease activity levels and severity are two different concepts and not essentially interchangeable.
Psoriatic arthritis (PsA) is a complex, chronic, multidomain inflammatory disease. There have been many studies and indices focusing on identifying and classifying disease activity levels. However, much less attention has been paid to the concept of disease severity, which is an important factor in determining treatment approach. Moreover, disease activity level is not always related to or predictive of disease severity. Further, those with more severe ailments are less likely to respond to treatment and achieve remission. Generally, factors like female gender, high levels of inflammation, and obesity are considered important predictors of worse clinical outcomes.
This retrospective study, published in the journal Rheumatology and Therapy, aimed to identify severe PsA patients using the modified Composite Psoriatic Disease Activity Index (mCPDAI), evaluate clinical differences in severe and non-severe patients, and identify clinical factors associated with severe PsA. The study also examined the agreement between mCPDAI and other disease activity measures.
Disease Activity Not Essentially Suggestive of Disease Severity
The study identified 177 patients with peripheral PsA. The findings showed a substantial proportion of PsA patients (36.1%) had severe disease. However, over time, the prevalence of severe PsA decreased, suggesting potential reversibility with treatment.
Notably, while female PsA patients generally tend to have higher disease activity, worse scores on outcome measures, and reduced response and persistence to advanced biologic treatments compared to their male counterparts, male gender and severe skin involvement emerged as factors associated with persistent, severe PsA.
The study underscored a crucial distinction between disease severity and activity, revealing that disease activity measures capture certain aspects of severity, but not all. The mCPDAI had good predictive value for estimating disease severity, although further validation remains imperative.
The study limitations included a lack of radiographic progression data and the exclusive reliance on clinical indices for disease assessment, potentially overlooking radiographic damage and other disease manifestations. The study especially overlooked factors like the clinical form and location of the disease, something that is essential for understanding disease severity. The researchers also accepted that mCPDAI might not be a perfect candidate index to assess severity, but they used it due to a lack of other, more reliable tools.
The Bottom Line
In sum, the study demonstrated the interplay between disease severity and activity in PsA. However, it was found that higher levels of disease activity and pain are predictive of severe disease, but disease activity and severity are not interchangeable concepts. Thus, the study underscored the necessity for refined severity assessment tools and personalized treatment approaches. Further inquiry in this direction holds promise for enhancing understanding and management of PsA, ultimately resulting in improved patient outcomes.
Source:
Lubrano, E., Scriffignano, S., & Perrotta, F. M. (2024b). Clinical characteristics of “Severe” peripheral psoriatic arthritis: A retrospective analysis of a longitudinal cohort. Rheumatology and Therapy. https://doi.org/10.1007/s40744-024-00667-0
