Rheumatic Conditions as Risk Factors for Self-Harm: A Retrospective Cohort Study

Objective: To examine the risk of self-harm in rheumatic conditions.

Methods: We conducted a retrospective cohort study using data from the Clinical Practice Research Datalink. Patients with ankylosing spondylitis, fibromyalgia, osteoarthritis, or rheumatoid arthritis were identified from 1990 to 2016 and matched to patients without these conditions. Incident self-harm was defined by medical record codes following a rheumatic diagnosis. Incidence rates (per 10,000 person-years) were reported for each condition, both overall and year-on-year (2000–2016). Cox regression analysis determined risk (hazard ratio [HR] and 95% confidence interval [95% CI]) of self-harm for each rheumatic cohort compared to the matched unexposed cohort. Initial crude analysis was subsequently adjusted and stratified by age and sex. Due to nonproportionality over time, osteoarthritis was also stratified by disease duration (<1 year, ≥1 to <5 years, ≥5 to <10 years, and ≥10 years).

Results: The incidence of self-harm was highest in patients with fibromyalgia (HR 25.12 [95% CI 22.45–28.11] per 10,000 person-years) and lowest for osteoarthritis (HR 6.48 [95% CI 6.20–6.76]). There was a crude association with each rheumatic condition and self-harm, except for ankylosing spondylitis. Although attenuated, these associations remained after adjustment for fibromyalgia (HR 2.06 [95% CI 1.60–2.65]), rheumatoid arthritis (HR 1.59 [95% CI 1.20–2.11]), and osteoarthritis (1 to <5 years HR 1.12 [95% CI 1.01–1.24]; ≥5 to <10 years HR 1.35 [95% CI 1.18–1.54]). Age and sex were weak effect modifiers for these associations.

Conclusion: Primary care patients with fibromyalgia, osteoarthritis, or rheumatoid arthritis (but not ankylosing spondylitis) are at increased risk of self-harm compared to people without these rheumatic conditions. Clinicians need to be aware of the potential for self-harm in patients with rheumatic conditions (particularly fibromyalgia), explore mood and risk with them, and offer appropriate support and management.