title: Can we predict which patients with refractory dyspnea will respond to opioids?
abstract: BACKGROUND
  Dyspnea is frequently encountered in end-stage diseases even when reversible issues are addressed. Which clinical factors best define patient subpopulations that will most predictably benefit from opioids in this clinical setting?
  
  
  METHODS
  Thirty-eight patients with refractory dyspnea were randomized to an 8-day crossover trial of 4 days of 20 mg sustained release morphine or placebo, switching arms on day 5 (Clinical Trial Registry Number: ACTRN012607000075482). Dyspnea was measured on a 100-mm visual analogue scale (VAS). Day 4 and day 8 morning and evening VAS scores were the primary outcome. Correlation between baseline dyspnea and response to opioids was explored; potentially important clinical predictors tested with two-sided Student's t test.
  
  
  RESULTS
  In this exploratory study, no relationship could be defined between baseline dyspnea and response to opioids (Spearman correlation 0.03, p = 0.88). The study was not powered to define other predictors, but younger age, better functional status, and significant cardiac findings on entry to the study deserve further prospective evaluation in a larger cohort.
  
  
  CONCLUSIONS
  Phase 4 pharmaco-vigilance trials are needed in palliative care to define people who are most likely to experience a net benefit from treatment such as opioids for refractory dyspnea.
authors.affiliation: Department of Palliative and Supportive Services, Division of Medicine, South Australia, Australia. david.currow@rgh.sa.gov.au
authors.forename: David C
authors.initials: DC
authors.lastname: Currow
authors.forename: John
authors.initials: J
authors.lastname: Plummer
authors.forename: Peter
authors.initials: P
authors.lastname: Frith
authors.forename: Amy P
authors.initials: AP
authors.lastname: Abernethy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004417:Dyspnea / Q000188:drug therapy*; D005260:Female; D006305:Health Status Indicators; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010865:Pilot Projects; D011379:Prognosis; D011795:Surveys and Questionnaires; D017211:Treatment Failure; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid