A panel of four biomarkers of cartilage metabolism, metabolic syndrome, and inflammation could help physicians to distinguish between osteoarthritis and psoriatic arthritis, new research suggests.

Dr. Vinod Chandran

Dr. Vinod Chandran

Such a test for distinguishing between the two conditions, which have “similarities in the distribution of joints involved,” could offer a way to make earlier diagnoses and avoid inappropriate treatment, according to Vinod Chandran, MD, PhD, of the department of medicine at the University of Toronto and Toronto Western Hospital and his colleagues. Dr. Chandran was first author on a study published online in Annals of the Rheumatic Diseases that analyzed serum samples from the University of Toronto Psoriatic Arthritis Program and University Health Network Arthritis Program for differences in certain biomarkers from 201 individuals with osteoarthritis, 77 with psoriatic arthritis, and 76 healthy controls.

The samples were tested for 15 biomarkers, including those related to cartilage metabolism (cartilage oligomeric matrix protein and hyaluronan), to metabolic syndrome (adiponectin, adipsin, resistin, hepatocyte growth factor, insulin, and leptin), and to inflammation (C-reactive protein, interleukin-1-beta, interleukin-6, interleukin-8, tumor necrosis factor alpha, monocyte chemoattractant protein–1, and nerve growth factor).

Researchers found that levels of 12 of these markers were different in patients with psoriatic arthritis, osteoarthritis, or controls, and 9 markers showed altered expression in psoriatic arthritis, compared with osteoarthritis.

Further analysis showed that levels of cartilage oligomeric matrix protein, resistin, monocyte chemoattractant protein–1, and nerve growth factor were significantly different between patients with psoriatic arthritis and those with osteoarthritis. The ROC curve for a model based on these four biomarkers that also incorporated age and sex had an area under the curve of 0.9984.

Researchers then validated the four biomarkers in an independent set of 75 patients with osteoarthritis and 73 with psoriatic arthritis and found these biomarkers were able to discriminate between the two conditions beyond what would be achieved based on age and sex alone.

The authors noted that previous research has observed high expression of monocyte chemoattractant protein–1 and resistin in patients with psoriatic arthritis when compared with those with osteoarthritis.

Nerve growth factor has been seen at elevated levels in the synovial fluid of individuals with osteoarthritis and is known to play a role in the chronic pain associated with that disease.

Similarly, higher cartilage oligomeric matrix protein levels are associated with a higher risk of knee osteoarthritis.

However, the authors noted that individuals with osteoarthritis in the study were all undergoing joint replacement surgery and therefore may not be typical of patients presenting to family practices or rheumatology clinics.

The University of Toronto Psoriatic Arthritis Program is supported by the Krembil Foundation. No conflicts of interest were declared.

SOURCE: Chandran V et al. Ann Rheum Dis. 2019 Mar 25. doi: 10.1136/annrheumdis-2018-214737.