Common Mental Disorders Within Chronic Inflammatory Disorders: A Primary Care Database Prospective Investigation

Abstract

Background: There is inconsistent evidence about the association between inflammatory disorders with depression and anxiety onset in a primary care context. The study aimed evaluate the risk of depression and anxiety within multisystem and organ-specific inflammatory disorders. Methods: Prospective cohort study with primary care patients from the UK Clinical Practice Research Datalink diagnosed with an inflammatory disorder between 1st of January 2001 and 31st of December 2016. These patients were matched on age, gender, practice, and index date with patients without an inflammatory disorder. The study exposures were seven chronic inflammatory disorders. Clinical diagnosis of depression and anxiety represented the outcome measures of interest. Findings: Among 538,707 participants, the incidence of depression ranged from 14 per 1000 person-years (severe psoriasis) to 9 per 1000 person-years (systemic vasculitis), substantively higher compared to their comparison group (5 to 7 per 1000 person-years). Hazard ratios (HR) of multiple depression and anxiety events were 16% higher within inflammatory disorders (HR, 1·16, 95%CI 1·12-1·21, p<0.001) compared to the matched comparison group. The incidence of depression and anxiety was strongly associated with the age at inflammatory disorder onset. The overall HR estimate for depression was 1·90 (95%CI, 1·66-2·17, p<0.001) within early onset disorder (<40 years of age) and 0.93 (95%CI, 0·90- 1·09, p=0·80) within late-onset of disorder (≥60 years of age). Interpretation: Primary care patients with inflammatory disorders have elevated rates of depression and anxiety incidence, particularly those patients with early onset inflammatory disorders. This finding may reflect the impact of the underlying disease on patients' quality of life, partially mediated by the underlying chronic inflammation. Funding Statement:The authors state: None. Declaration of Interests: The authors state: None to be declared. Ethics Approval Statement: The study was approved by the Independent Scientific Advisory Committee (reference No. 17_036RA).