title: Botulinum toxin for achalasia: long-term outcome and predictors of response.
abstract: OBJECTIVE
  Botulinum toxin injection into the lower esophageal sphincter of patients with achalasia results in effective short-term relief of symptoms. The aims of this study were to examine the long-term outcome of these patients and to determine the predictors of response to this therapy.
  
  
  METHODS
  Thirty-one patients with achalasia treated with botulinum toxin were followed up prospectively for a median duration of 890 days.
  
  
  RESULTS
  Twenty-eight patients improved initially, but only 20 patients had sustained improvement beyond 3 months; the latter patients were classified as responders. The response rate was greater in patients older than 50 years of age (82% vs. 43% in younger patients; P = 0.03) and in patients with vigorous achalasia (100% vs. 52% with classic achalasia; P = 0.03). Duration of illness, previous dilation, and baseline radiological characteristics did not influence outcome. Nineteen responders eventually had relapse after a median duration of 468 days (range, 153 - 840 days). Fifteen of these patients received a second injection with satisfactory results obtained in the majority of patients.
  
  
  CONCLUSIONS
  Botulinum toxin is an effective treatment for achalasia in about two thirds of patients, with a duration of response averaging 1.3 years. Age and type of achalasia seem to be important predictors of response.
authors.affiliation: Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Pasricha
authors.forename: R
authors.initials: R
authors.lastname: Rai
authors.forename: W J
authors.initials: WJ
authors.lastname: Ravich
authors.forename: T R
authors.initials: TR
authors.lastname: Hendrix
authors.forename: A N
authors.initials: AN
authors.lastname: Kalloo
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D018726:Anti-Dyskinesia Agents / Q000627:therapeutic use*; D001905:Botulinum Toxins / Q000627:therapeutic use*; D015331:Cohort Studies; D004931:Esophageal Achalasia / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012008:Recurrence
chemical_list: D018726:Anti-Dyskinesia Agents; D001905:Botulinum Toxins