Sonographic enthesitis has been identified as a potential marker of radiographic joint damage in PsA. In addition, the relationship between HLA genetic susceptibility markers has been examined, with HLA-B27 being associated with more severe sonographic enthesitis in PsA. Through international initiatives, future steps include the development of sonographic scoring systems in PsA.

• Polachek A, Cook R, Chandran V, Gladman D, Eder L. The association between sonographic enthesitis and radiographic damage in psoriatic arthritis. Arthritis Res Ther. 2017; 19: 189.
• Polachek A, Cook R, Chandran V, Abji F, Gladman D, Eder L. The association between HLA genetic susceptibility markers and sonographic enthesitis in psoriatic arthritis. Arthritis Rheumatol. 2017.
• Tom S, Zhong Y, Cook R, Aydin SZ, Kaeley G, Eder L. Development of preliminary ultrasonographic enthesitis score in psoriatic arthritis – GRAPPA ultrasound working group. J Rheumatol 2019; 46: 384-90

An additional field of research is the epidemiology of psoriatic disease, with an emphasis on the pre-clinical phases of PsA. These studies have suggested that a preclinical phase, characterized by non-specific musculoskeletal systems (e.g. joint pain, fatigue), exists in PsA patients prior to the diagnosis of the disease. Other risk factors, such as smoking, severe psoriasis, nail pitting and uveitis, have shown to be predictive of the development of PsA in patients with psoriasis. 

• Eder L, Polachek A, Rosen CF, Chandran V, Cook R, Gladman DD. The development of psoriatic arthritis in patients with psoriasis is preceded by a period of nonspecific musculoskeletal symptoms: A prospective cohort study. Arthritis Rheumatol 2017; 69: 622-629. 
• Eder L, Haddad A, Rosen CF, Lee KA, Chandran V, Cook RJ, Gladman DD. The incidence and risk factors for psoriatic arthritis in patients with psoriasis: A prospective cohort study. Arthritis Rheumatol 2016; 68: 915-23.
• Eder L, Shanmugarajah S, Thavaneswaran A, Chandran V, Rosen CF, Cook RJ, Gladman DD. The association between smoking and the development of psoriatic arthritis among psoriasis patients. Ann Rheum Dis. 2012; 71:219-24. 

These studies contributed to a growing body of knowledge about cardio-metabolic diseases in psoriatic patients. A significant proportion of patients with PsA were found to develop cardiovascular events, such as heart attack and stroke, during the course of their disease. Increased cardiovascular risk is associated with a combination of traditional cardiovascular risk factors and disease activity. Importantly, general risk prediction algorithms, such as the Framingham Risk Score, were found to underestimate risk and subclinical atherosclerosis in patients with psoriatic disease.

• Eder L, Joshi AA, Dey AK, Cook R, Siegel EL, Gladman DD, Mehta NN. TNF inhibitors are associated with reduced indices of subclinical atherosclerosis in patients with psoriatic disease. Arthritis Rheumatol. 2018; 70: 408-16
• Polachek A, Touma Z, Anderson M, Eder L. Risk of cardiovascular morbidity in psoriatic arthritis: A meta-analysis of observational studies. Arthritis Care Res (Hooboken) 2017; 69: 67-74.
• Eder L, Wu Y, Chandran V, Cook R, Gladman DD. Incidence and predictors for cardiovascular events in patients with psoriatic arthritis. Ann Rheum Dis. 2016; 75: 1680-6.
• Eder L, Chandran V, Gladman DD. The Framingham risk score underestimates the extent of subclinical atherosclerosis in patients with psoriatic disease. Ann Rheum Dis. 2014; 73:1990-6