Predictive Factors Associated With Development Of Psoriatic Arthritis In Patients With Underlying Psoriasis

Background:Psoriatic arthritis (PsA) is a chronic inflammatory condition in which a delayed diagnosis will have health impacts including physical and psychological aspects. Thus, identification of risk factors and early diagnosis are crucial in clinical practice. In Malaysia, 13.7% of patients with underlying psoriasis develop PsA 1. However, there are limited data on the risk factors in developing PsA in these patients, not just in Malaysia but also in the Southeast Asia region.Objectives:To analyse sex, clinical features, comorbidities in patients with psoriasis and PsA, and the predictive factors of developing PsA in patients with underlying psoriasis.Methods:A retrospective study was carried out involving patients with a physician-verified diagnosis of psoriasis who were attending the dermatology and/or rheumatology clinics at the University of Malaya Medical Centre, Kuala Lumpur between 2015 to 2020. Data were retrieved from electronic medical records. Data collected included sex, age, body mass index (BMI), duration of psoriasis, socio-demographics, comorbidities, body area affected, severity of skin involvement, presence of nail involvement and systemic therapy used in treating psoriasis. Systemic therapy is defined as methotrexate, sulfasalazine and/or acitretin used before diagnosis of PsA. Patients with psoriasis who developed PsA had information collected on tender joint count, swollen joint count and erythrocyte sedimentation rate (ESR) at their initial visit to the rheumatologist. Logistic regression analyses were performed to identify the possible risk factors of developing PsA.Results:A total of 330 psoriasis patients which included 54.5% male and a mean age of 53 (standard deviation, SD 18.85) years were included. Eighty-three (25.0%) patients were diagnosed with PsA. Among patients with PsA, 39.8% were males with a mean age of 54 (SD 15.79) years. Majority of the PsA patients were ethnic Malay (45.8%), followed by 28.9% Chinese and 25.3% Indian. The median duration of developing PsA was at 36 (IQR 3.5 - 114) months after the diagnosis of psoriasis. 12.3% presented with active polyarthritis at the initial diagnosis of PsA. There was a significant difference in the use of systemic therapy in females, in which there was a higher rate of systemic therapy used in female PsA patients prior to developing PsA as compared to females with psoriasis who did not develop PsA (n=24, 48% vs n=16, 16%; p < 0.001). There was no significant association between ethnicity, education level, comorbidities, BMI, body area affected and family history of psoriasis with development of PsA. The predictive factors in developing PsA are females (OR = 3.14, 95% CI 1.77,5.58), presence of nail involvement (OR = 3.72, 95% CI 1.91,7.26) and the use of systemic therapy (OR = 3.04, 95% CI 1.70,5.43), (all p values <0.001).Conclusion:This study highlighted that female sex, presence of nail involvement and use of systemic therapy prior to PsA diagnosis are predictive risk factors in developing PsA among patients with underlying psoriasis. Further prospective studies with larger cohorts are needed to better delineate these risk factors.References:[1]Mohd Affandi A, Khan I, Ngah Saaya N. Epidemiology and Clinical Features of Adult Patients with Psoriasis in Malaysia: 10-Year Review from the Malaysian Psoriasis Registry (2007-2016). Dermatology research and practice. 2018;2018:4371471.Figure 1.Comorbidities among Patients with underlying Psoriasis and Psoriatic Arthritis (n=330)Chi-square test revealed that there was no significant difference between psoriasis and psoriatic arthritis (p > 0.05)Disclosure of Interests:WAI YANG LOO: None declared, FARIZ YAHYA Speakers bureau: speaker for Novartis, Gilead, AbbVie, Janssen, Eli Lilly, Zuellig-Pharma and Pfizer., Consultant of: consultancy work with Novartis, Gilead, AbbVie, Eli Lilly, Zuellig-Pharma and Pfizer., Grant/research support from: research grants from Novartis, Gilead, AbbVie, Boehringer-Ingelheim and Pfizer., WINN HUI HAN: None declared, NIK AIMEE AZIZAH FAHEM: None declared, SHIN SHEN YONG: None declared, Lydia Say Lee Pok: None declared, Zhenli Kwan Speakers bureau: Novartis, Zuellig, YING CHEW TEE: None declared.