Prevalence of depression and anxiety in patients with chronic non-malignant pain–A Danish register-linkage cohort study

Abstract

IntroductionAnxiety and depression disorders are common in patients with chronic pain. Studies using clinical interviews in patients with chronic pain report prevalence rates ranging between 30–54% for depression and 17–29% for anxiety. This is the first study using contacts with a hospital psychiatric ward to investigate prevalence of depression and anxiety in patients with chronic pain.ObjectivesEstimate the prevalence of anxiety and depression in patients with chronic pain referred for interdisciplinary treatment.AimsTo increase the knowledge about mental disorders and chronic pain in secondary health care.MethodsAll chronic pain patients referred to and treated at an interdisciplinary pain clinic at Odense university hospital, Denmark from 1 Jan 2005–13 Nov 2015 were included as participants. The Danish National Patient Register was used to collect information on contacts with a hospital psychiatric ward 10-year prior to the first contact at the pain clinic due to depression (ICD-10: F32-F33) and/or anxiety (ICD-10: F40-F41).ResultsIn total, 7204 patients (64% women; mean age: 48.2) were included. Altogether, 17.8% (95% CI: 16.9–18.7) of patients had contact to a psychiatric ward. The prevalence of unipolar depression were: 6.1% (95% CI: 5.5–6.6) and anxiety: 2.1% (95% CI: 1.8–2.5), while 0.7% (95% CI: 0.5–0.9) had both depression and anxiety.ConclusionsThe prevalence rates of depression and anxiety noted in this study were lower than those reported in previous studies. A hospital-based diagnosis seems likely to be less frequent than interview-based measures, yet, might have a higher validity due to the clinician-based assessment.Disclosure of interestThe authors have not supplied their declaration of competing interest.