Botulinum toxin for achalasia: Long-term outcome and predictors of response

Background & Aims: 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 a 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.