title: Psychiatric Comorbidity Is Associated Prospectively with Diminished Opioid Analgesia and Increased Opioid Misuse in Patients with Chronic Low Back Pain.
abstract: BACKGROUND
  Opioids are frequently prescribed for chronic low back pain (CLBP), but there are little prospective data on which patient subgroups may benefit. Psychiatric comorbidity, such as high levels of depression and anxiety symptoms (termed comorbid negative affect [NA]), is a common presentation and may predict diminished opioid analgesia and/or increased opioid misuse.
  
  
  METHODS
  The authors conducted a 6½-month prospective cohort study of oral opioid therapy, with an active drug/placebo run-in period, in 81 CLBP patients with low, moderate, and high levels of NA. Treatment included an opioid titration phase with a prescribing physician blinded to NA group assignment and a 4-month continuation phase, during which subjects recorded daily pain levels using an electronic diary. The primary outcome was the percent improvement in average daily pain, summarized weekly.
  
  
  RESULTS
  There was an overall 25% dropout rate. Despite the high NA group being prescribed a higher average daily dose of morphine equivalents, linear mixed model analysis revealed that the 24 study completers in each of the high NA and low NA groups had an average 21 versus 39% improvement in pain, respectively (P < 0.01). The high NA group also had a significantly greater rate of opioid misuse (39 vs. 8%, P < 0.05) and significantly more and intense opioid side effects (P < 0.01).
  
  
  CONCLUSIONS
  These results indicate that the benefit and risk considerations in CLBP patients with high NA versus low NA are distinctly different. Thus, NA is an important phenotypic variable to characterize at baseline, before deciding whether to prescribe opioids for CLBP.
authors.affiliation: From the Departments of Anesthesiology and Psychiatry (A.D.W.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and Departments of Anesthesiology (A.D.W., E.M., R.R.E., S.S.N., A.J.D., D.J., R.N.J.), Psychiatry (R.R.E., R.N.J.), Internal Medicine (J.N.K.), Orthopaedic Surgery (J.N.K.), and Physical Medicine and Rehabilitation (Z.I.), Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: Ajay D
authors.initials: AD
authors.lastname: Wasan
authors.forename: Edward
authors.initials: E
authors.lastname: Michna
authors.forename: Robert R
authors.initials: RR
authors.lastname: Edwards
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Katz
authors.forename: Srdjan S
authors.initials: SS
authors.lastname: Nedeljkovic
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Dolman
authors.forename: David
authors.initials: D
authors.lastname: Janfaza
authors.forename: Zach
authors.initials: Z
authors.lastname: Isaac
authors.forename: Robert N
authors.initials: RN
authors.lastname: Jamison
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology / Q000627:therapeutic use*; D059350:Chronic Pain / Q000175:diagnosis* / Q000188:drug therapy / Q000523:psychology; D015331:Cohort Studies; D015897:Comorbidity; D018592:Cross-Over Studies; D017831:Diagnosis, Dual (Psychiatry); D004311:Double-Blind Method; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000188:drug therapy / Q000523:psychology; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis* / Q000188:drug therapy / Q000523:psychology; D008875:Middle Aged; D009293:Opioid-Related Disorders / Q000175:diagnosis* / Q000523:psychology; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods; D011446:Prospective Studies
chemical_list: D000701:Analgesics, Opioid