Lihi Eder, MD, PhD, on the Prediagnosis Period in PsA

Results of a new study1 suggest that nonspecific musculoskeletal symptoms may precede the diagnosis of psoriatic arthritis (PsA).

These conclusions were made after the researchers conducted a population-based, matched cohort study of 462 patients with PsA and 2310 matched comparators. Using electronic medical records and administrative data, the researchers evaluated health care utilization related to musculoskeletal issues during a 5-year period prior to the diagnosis of PsA.

To find out more about the results, Consultant360 reached out to the lead author of the study, Lihi Eder, MD, PhD, who is an assistant professor of medicine at the University of Toronto and a scientist at the Women’s College Research Institute at the Women’s College Hospital in Toronto, Canada.

CONSULTANT360: Why is it important to understand the prediagnosis period for PsA?

Lihi Eder: One of the gaps in care for patients with PsA is the delayed diagnosis. Recent studies suggest that a proportion of patients with PsA presents with nonspecific musculoskeletal symptoms several years prior to the diagnosis. Better understanding of this prediagnosis period will allow earlier diagnosis and treatment of PsA and perhaps even prevention of the disease.

C360: What is the most important finding from your study for rheumatologists?

LE: Rheumatologists need be aware that, for some patients, it may take time to develop distinct and clear findings on physical examination, such as swollen joints. This means that when clinical suspicion for PsA is high, it may be better to continue following these patients, as they may present with PsA later. In addition, sensitive imaging tests such as ultrasound may help diagnose patients at earlier stages.

C360: The findings indicated that a prodromal PsA phase, characterized by nonspecific musculoskeletal symptoms may exist. How can this potentially impact the management of PsA?

LE: Our previous studies that focused on patients with psoriasis showed that the symptoms are nonspecific and may include pain, stiffness, and fatigue. The problem is that these symptoms are nonspecific and may be attributed to other causes such as osteoarthritis or fibromyalgia. Ultrasound of suspected joints and entheses may help detect subclinical inflammation. More studies are needed to find objective measures, such as laboratory markers, to help clinicians identify patients who are at high risk of progressing to PsA.

C360: What are the next steps in your research?

LE: Our group and others are focusing on investigating patients with psoriasis and musculoskeletal symptoms and trying to better define the constellation of musculoskeletal symptoms that characterize patients who will go on to develop PsA. I believe that we will require a combination of clinical characteristics along with imaging and laboratory tests to identify those patients. Having a tool that will provide an accurate estimate of the risk for PsA for an individual patient with psoriasis will be the first step in researching prevention studies for PsA.



  1. Eder L, Tu K, Rosen CF, et al. Health care utilization for musculoskeletal issues during the pre‐diagnosis period in psoriatic arthritis – a population‐based study [published online January 20, 2020]. Arthritis Care Res (Hoboken).