PATTERNS OF PSORIATIC-ARTHRITIS IN ORIENTALS

Objective. To determine the clinical features of psoriatic arthritis ( PsA) in a multiethnic Oriental population and to study the effect of e thnicity on disease patterns, Methods. A retrospective study of 80 pat ients with PsA seen at either a rheumatology or dermatology referral c enter. Patients and case records were reviewed and data abstracted acc ording to a standard protocol. Eighty consecutive patients with psoria sis without PsA seen at the dermatology center were recruited as contr ols, Results, Asymmetric polyarthritis developing in the 4th decade wi th an equal male to female ratio was the commonest pattern of arthriti s among Chinese, Indians, and Malays. Clinically apparent lumbar spond ylitis was significantly more common in Indians than Chinese(10/11 vs 11/20, respectively; p = 0.046), although the prevalence of lumbar spo ndylitis was similar in all ethnic groups, Eighty-nine percent of subj ects required nonsteroidal antiinflammatory drugs and 51% required dis ease modifying antirheumatic drugs at some time for control of joint d isease, PsA was significantly more common among Indians compared to th e ethnic distribution of the Singapore population (p < 0.000001). Mult iple logistic regression identified Indian ethnicity as a risk factor for the development of PsA (OR 2.39, 95% confidence interval 1.02 to 5 .60). Conclusion. The commonest pattern of PsA in all ethnic groups wa s asymmetric polyarthritis, Ethnicity affected the development and pre sentation of PsA in our series: Indians with psoriasis had double the risk of developing PsA compared to Chinese with psoriasis, and lumbar spondylitis when present in Chinese subjects was asymptomatic in 45%, being detectable only on radiological examination.