Another report at the ACR annual meeting last October looked at the incidence of physician visits for nonspecific musculoskeletal symptoms during each of the 5 years preceding diagnosis of PsA. A prior report from Dr. Eder and her associates had documented in an observational cohort of 410 patients with psoriasis that, prior to development of PsA, patients often had nonspecific musculoskeletal symptoms of joint pain, fatigue, and stiffness that constituted a “preclinical” phase (Arthritis Rheumatol. 2017 March;69[3]:622-9).
In October, Dr. Eder reported how the appearance of musculoskeletal symptoms played out in terms of physician visits. She and her associates analyzed data from an Ontario health insurance database that included about 430,000 Ontario patients seen by 466 primary care physicians, which included 462 patients with a new diagnosis of PsA and 2,310 matched controls. The results showed that, in every year during the 5 years preceding diagnosis of PsA, the patients who would wind up getting diagnosed had roughly twice the number of visits to a primary care physician each year for nonspecific musculoskeletal issues. A similar pattern of doubled visits occurred for people prior to their PsA diagnosis going to physicians who specialize in musculoskeletal conditions, and when the analysis focused on visits to rheumatologists, patients who went on to get diagnosed with PsA had a nearly sevenfold increased rate of these visits, compared with controls, for each of the 5 years preceding their PsA diagnosis (Eder L et al. Arthritis Rheumatol. 2018;70[suppl 10]: Abstract 967).
These results “highlight that in many patients PsA is not an acute disease that starts suddenly. In many patients, there is a period when the patient experiences musculoskeletal symptoms and sees a primary care physician or rheumatologist and may be diagnosed with something that is not PsA. That means that the delay in diagnosis [of PsA] may have happened because the patients were misdiagnosed. It reinforces the need for better diagnostic tools,” Dr. Eder said. “We have focused on getting these patients to see a rheumatologist earlier, but that may not be enough. These patients may not receive routine follow-up; we need to do more follow-up on patients like these.” Diagnosing PsA early means earlier treatment, a better chance of reaching remission, less chance of permanent joint damage, and better quality of life.
The challenges of making an early diagnosis were also documented in a study reported by Dr. Ogdie during the June 2018 annual congress of the European League Against Rheumatism. Dr. Ogdie reported on the survey responses of 203 patients who said they had been diagnosed with PsA whose index diagnosis was a median of 6 years before they completed the survey. A total of 195 of these patients, or 96%, said that they had received at least one misdiagnosis prior to their PsA diagnosis (Odgie A et al. Ann Rheum Dis. 2018;77[Suppl 2]:163. Abstract THU0292). The most common misdiagnoses were psychosomatic disease, reported by 27% of the patients; osteoarthritis in 22%; anxiety or depression in 18%; and an orthopedic problem in 18%. (Patients could report more than one type of misdiagnosis.)
The results “showed that patients often had substantial delays and misdiagnoses before they received a PsA diagnosis,” Dr. Ogdie and her associates concluded. Although the CASPAR classification criteria may be the agreed on PsA definition, recent findings suggest a pre-PsA stage exists with musculoskeletal and other abnormalities. “How may we diagnose ‘pre-PsA’? How might we capture this transition phase from psoriasis to PsA before the CASPAR criteria are fulfilled,” she wondered in an interview. “If we could stop PsA before it is clinically relevant, that could dramatically change the course of the disease. This is a big need in the field right now.”
Weight loss and other interventions
Aside from treating psoriasis and perhaps putting a patient with psoriasis in a PsA-prevention trial, one of the best ways to prevent PsA may be weight loss.
Penn Medicine
Dr. Alexis Ogdie-Beatty and Dr. Joel Gelfand
Results from “some studies suggest that being overweight increases the risk for developing PsA. Obesity also exacerbates skin psoriasis, makes treatment less effective, and further increases the risk of cardiometabolic diseases associated with psoriasis,” Dr. Gelfand said. “All patients with psoriatic disease should be educated about the importance of maintaining a healthy body weight.”
“Several studies suggest that obesity is a risk factor for developing PsA. Obesity likely plays a role in driving or contributing to inflammation in psoriatic disease,” said Dr. Reddy, who noted that other PsA risk factors include nail psoriasis and first-degree relatives with PsA. Dr. Ogdie also cited uveitis and prior joint trauma as other risk factors.
“Strong observational data link obesity and PsA incidence. I talk to psoriasis patients about weight control, and selected patients could even consider bariatric surgery,” Dr. Eder said. Losing at least 5% of body mass index can make a difference, she added.
At the 2018 annual meeting of the American College of Rheumatology, researchers from the University of Bath (England) reported results from a retrospective, observational study of more than 90,000 people with recent-onset psoriasis; they found that people with an obese BMI had twice the rate of progression to PsA when compared with people with a normal BMI. Overweight people had a nearly 80% higher rate of incident PsA (Green A et al. Arthritis Rheumatol. 2018;70[Suppl 10]: Abstract 2134).
Hints have also emerged that new approaches to treating psoriasis also could help to keep PsA precursors at bay. One recent example from researchers at the University of Leeds (England) was a phase 2 study of 73 patients with moderate to severe psoriasis but no PsA who underwent ultrasound screening of their entheses for signs of inflammatory changes. The 23 patients underwent 52 weeks of treatment with the drug ustekinumab (Stelara), an antagonist of interleukin-12 and -23 that is approved for U.S. marketing to treat both psoriasis and PsA. After 24 weeks on treatment, their mean inflammation scores had dropped by more than 40%, and the effect persisted through 52 weeks of treatment (Arthritis Rheum. 2018 Nov 22. doi: 10.1002/art.40778).
Despite this promise, the researchers “haven’t looked long enough or in enough people to see whether this actually stops patients from developing PsA,” Dr. Coates commented. It also remains unclear whether this or another ultrasound abnormality detectable in joints or entheses is a reliable predictor of PsA, she noted.
“We still have a lot to learn about how to classify patients as high risk” for PsA, Dr. Ogdie concluded.
Dr. Eder has received research and educational grants from AbbVie, Amgen, Celgene, Lilly, Novartis, and UCB. Dr. Coates has received honoraria, research funding, or both from more than a dozen companies. Dr. Reddy has been a consultant to AbbVie, Novartis, Pfizer, and UCB. Dr. Merola has been a consultant to AbbVie, Celgene, GlaxoSmithKline, Janssen, Lilly, Novartis, Samumed, Sanofi, and UCB and has received research grants from Aclaris, Biogen, Incyte, Novartis, Pfizer, and Sanofi. Dr. Gelfand has been a consultant, adviser, or both to more than a dozen companies. Dr. Ogdie has been a consultant to AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Corrona, Lilly, Novartis, Pfizer, and Takeda.