title: Breakthrough pain in opioid-treated chronic non-malignant pain patients referred to a multidisciplinary pain centre: a preliminary study.
abstract: BACKGROUND
  Breakthrough pain (BTP) has not formerly been discussed as such in chronic non-malignant pain patients referred to pain centres and clinics. The purpose of the study was to investigate the prevalence, characteristics and mechanisms of BTP in opioid-treated chronic non-malignant pain patients referred to a pain centre and to assess the short-term effects of pain treatment.
  
  
  METHODS
  Patients were assessed at referral (T(0)) and after a treatment period of 3 months (T(3)) using the visual analogue scale (VAS) of the brief pain inventory (BPI) within somatic nociceptive, neuropathic and/or visceral pain conditions, the mini mental state examination (MMSE) and the hospital anxiety and depression scale (HADS). The main treatment intervention from T(0) to T(3) was to convert short-acting oral opioids to long-acting oral opioids and to discontinue on demand and parenteral use of opioids.
  
  
  RESULTS
  Thirty-three patients were assessed at T(0) and 27 at T(3). The prevalence of BTP declined significantly from T(0) (90%) to T(3) (70.4%). Worst, least, average and current pain intensities as well as duration of BTP were significantly reduced from T(0) to T(3.) The majority of BTPs were exacerbation of background pain assumed to be of the same pain mechanisms. High average pain intensity (BPI) was significantly associated with high scores for both anxiety and depression (HADS).
  
  
  CONCLUSIONS
  BTP in chronic non-malignant pain patients seems to be surprisingly frequent and severe. Stabilizing the opioid regimen seems to reduce pain intensity in general as well as the intensity and duration of BTP. Average pain intensity was associated with anxiety and depression.
authors.affiliation: Multidisciplinary Pain Center, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark. hojsted@rh.dk
authors.forename: J
authors.initials: J
authors.lastname: Højsted
authors.forename: P R
authors.initials: PR
authors.lastname: Nielsen
authors.forename: J
authors.initials: J
authors.lastname: Eriksen
authors.forename: O B
authors.initials: OB
authors.lastname: Hansen
authors.forename: Per
authors.initials: P
authors.lastname: Sjøgren
mesh_terms: D000284:Administration, Oral; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use*; D002908:Chronic Disease; D003718:Denmark; D006801:Humans; D010146:Pain / Q000188:drug therapy*; D018710:Pain Clinics; D012017:Referral and Consultation; D012420:Running; D017211:Treatment Failure; D016896:Treatment Outcome; D016138:Walking
chemical_list: D000701:Analgesics, Opioid