Ankylosing Spondylitis Patients at Risk for Self-Harm

Ingrid Hein

June 15, 2018

AMSTERDAM — People with ankylosing spondylitis are nearly twice as likely as those in the general population to deliberately harm themselves, research from a Canadian study shows.

"We haven't really identified the cause," said senior investigator Nigil Haroon, MD, PhD, from the University of Toronto. It could be pain, anxiety, stress, lack of social support, or isolation, all of which can lead to depression, he explained.

"It may not be the same reason for everybody, but we do think depression plays a role," he told Medscape Medical News.

Ankylosing spondylitis and rheumatoid arthritis are the "two most common inflammatory diseases we see, and we wanted more data on the risk for serious mental-health outcomes following a diagnosis," he said.

To that end, Haroon and his colleagues assessed the health records of 53,240 patients with rheumatoid arthritis and 13,964 with ankylosing spondylitis in the largest study to date to evaluate self-harm. Patients with a history of mental illness and those who had harmed themselves before their diagnosis were excluded from the analysis.

A comparator cohort from the general population was matched for age and sex at a 1 to 4 ratio.

The study outcome was the number of people who deliberately harmed themselves and then presented to the emergency department from April 1, 2002 to March 31, 2016.

"The administrative database gave us several thousand patient-years of follow-up, which is needed to study rare outcomes," Haroon explained.

Largest Study of Self-Harm

Patients with ankylosing spondylitis were almost twice as likely to harm themselves as those in the matched group (incidence rate [IR], 6.79 vs 3.19/10,000 person-years; adjusted hazard ratio [HR], 1.82; 95% confidence interval [CI], 1.26 - 2.62).

Patients with rheumatoid arthritis were at increased risk for self-harm before covariate adjustment (IR, 3.51 vs 2.45/10,000 person-years; HR, 1.43; 95% CI 1.16 - 1.75), but not after adjustment (HR, 1.09; 95% CI, 0.88 - 1.36).

The most frequent methods of self-harm were poisoning (64% in the ankylosing spondylitis group and 81% in the rheumatoid arthritis group) and self-mutilation (36% and 18%, respectively).

These are rare but "very important events," said Haroon. A rheumatologist with 300 patients might see only one or two present to the emergency department for self-harm over 10 years, but "it's important to recognize the signs."

"We needed a large population to determine risk," he explained. Because the team only assessed patients who presented to the emergency department, the study numbers are likely conservative, he warned.

A recent study showed that the risk for depression is elevated in patients with psoriasis, psoriatic arthritis, and ankylosing spondylitis (J Eur Acad Dermatol Venereol. 2017;31:1168-1175).

"Understanding the mechanisms that contribute to deliberate self-harm attempts will help tailor future preventive strategies to reduce morbidity associated with this serious mental-health outcome," said Thomas Dörner, MD, from Charité University Hospitals in Berlin.

The medical community is focused on controlling inflammation and limiting damage to the joints, but as more data become available, we are learning about other effects of the disease, said Haroon.

Not Just Joints

"We are now also concentrating on heart disease — strokes and heart attacks — because these patients have an increased chance of dying from cardiovascular events," he explained. But mental health is often ignored.

"For any chronic disease, we need to concentrate on mental health, low mood, and depression," he explained. It is important to talk to patients to find out if they are losing interest in activities they were doing before, have stopped exercising, or have narrowed their social circle. "If you spend a little time with them, they do tell you. If you do the interview too quickly, they don't," he pointed out.

For some patients who have become isolated because of their disease, a trip to the clinic can be an important social event, he said.

Haroon's research team was funded by the Division of Rheumatology Pfizer Research Chair at the University of Toronto. Dörner has disclosed no relevant financial relationships.

European League Against Rheumatism (EULAR) Congress 2018: Abstract OPO296. Presented June 15, 2018.

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