Psoriatic arthritis: An assessment of clinical, biochemical and radiological features in a single-centre South African cohort.

BACKGROUND: Although psoriatic arthritis (PsA) is a well-documented clinical entity, epidemiological, clinical and radiological studies of South African (SA) patients are scarce. OBJECTIVES: To assess clinical, biochemical and radiological features in a single-centre SA cohort. METHODS: We conducted a prospective assessment of the clinical, biochemical and radiological features of 384 consecutive patients with PsA seen at the rheumatology clinic at Prince Mshiyeni Memorial Hospital, Durban, SA, between January 2007 and December 2013. Patients were assessed at enrolment and 6 months after enrolment. They were classified into five groups as described by Moll and Wright, being entered into the group that best described the clinical manifestations. Clinicopathological characteristics recorded at enrolment were age at the time of examination, racial background, personal and family medical history, age and symptoms at the onset of PsA, pattern of joint involvement, joint pain, and the relationship between joint pain and the onset of PsA. RESULTS: Of the patients, 59.1% had a polyarticular presentation indistinguishable from rheumatoid arthritis, 19.0% had distal interphalangeal involvement, 9.1% had spondyloarthropathy, 11.9% had oligoarthritis and 0.9% had arthritis mutilans. The epidemiological trends (male/female ratio 1.45:1, mean age at onset of arthritis 50.2 (standard deviation 11.8) years, female preponderance in the polyarticular group and male preponderance in the spondyloarthropathy and oligoarticular groups) were similar to trends published elsewhere. A notable characteristic of our cohort was the complete absence of black South Africans with PsA. CONCLUSIONS: The complete absence of black South Africans with PsA is interesting. We anticipate that our findings will prompt genetic studies to isolate both protective and susceptibility genes for further elucidating PsA.

Summary of Sensitivity and Specificity for Psoriatic Arthritis in a South African Cohort according to Classification Criteria.

OBJECTIVE: To evaluate the sensitivity and specificity of the classification criteria for psoriatic arthritis (PsA) in a South African cohort. METHODS: Data from consecutive patients with PsA and other chronic inflammatory arthritides were collected prospectively. Subjects were classified according to the classification criteria. The sensitivity and specificity in each group of patients were compared with a clinical diagnosis made by a rheumatologist. RESULTS: The European Spondylarthropathy Study Group criteria exhibited the lowest sensitivity followed by the Moll and Wright criteria. The sensitivity and specificity of the ClASsification for Psoriatic ARthritis (CASPAR) criteria were 98.4% and 99.7%, respectively. CONCLUSION: The CASPAR criteria were evaluated in our cohort and they performed well.