Four biomarkers can differentiate between osteoarthritis and psoriatic arthritis, Canadian research shows.
If validated in larger prospective studies, the panel of four biomarkers could be used in clinical practice to accurately identify patients with OA or PsA who otherwise have similar symptoms on initial presentation and may be misdiagnosed, according to rheumatologists from Toronto Western Hospital.
The biomarkers were among 15 whose levels were initially compared in 201 patients with OA, 77 patients with PsA and 76 healthy control patients.
Overall, 12 markers showed significant differences in levels between the patients groups. However in multivariate analysis only four were independently associated with PsA versus OA: cartilage oligomeric matrix protein (COMP, a marker of cartilage metabolism); resistin (a marker of metabolic syndrome) and two markers of inflammation and immune response, monocyte chemoattractant protein-1 (MCP-1) and nerve growth factor (NGF).
These four biomarkers were found to have good discriminatory value, with an ROC curve having an AUC of 0.99 compared to a value of 0.87 for a model based on age and sex alone.
The four biomarkers were then measured in an independent validation cohort of 75 patients with OA and 73 with PsA. This also confirmed a significant difference in the AUC of the ROC curves for biomarkers vs demographic features (0.99 vs 0.87) for discriminating PsA from OA.
Writing in Annals of Rheumatology, the study authors said the findings were in line with previous studies that had shown high levels of markers such as resistin and MCP-1 in the serum of patients with PsA compared to those with OA.
However, while the initial results were promising they would need to be confirmed in larger prospective studies in real world populations of patients with OA and PsA.
The researchers said it would be very useful to have an objective measure that could discriminate between the two conditions, which affected similar joints and could be difficult to differentiate even with high resolution imaging.
Some patients presumed to have PsA did not respond to biologics, and this might be because they were misdiagnosed OA patients, they noted.
“With the development of biological therapies, the inclusion of soluble biomarkers in the diagnosis and treatment of PsA and OA would facilitate a personalised medicine approach to patient care,” they wrote.
“After further verification and validation, these markers could provide a valuable tool for the improved diagnosis and management of both OA and PsA thus resulting in improved patient outcomes,” they concluded.