title: A prospective study of the clinical features, manometric findings, incidence and prevalence of achalasia in Singapore.
abstract: BACKGROUND
  This study aimed to describe the clinical features, manometric findings, prevalence and incidence of achalasia in Singapore.
  
  
  METHODS
  A total of 615 new patients referred for oesophageal manometry between 1989 and 1996 were examined prospectively. Twenty-four men and 25 women fulfilled the manometric and clinical criteria for achalasia.
  
  
  RESULTS
  Their median age of onset of symptoms was 37 years (range 15-71) and 37% first developed symptoms after the age of 50 years. The presenting symptoms were dysphagia (100%), regurgitation (80%), weight loss (67%) and chest discomfort (33%). Five patients (10%) had a history of benign (mostly autoimmune) thyroid disorders. Endoscopy was reported as normal in 10/43 patients (23%) and achalasia was suggested in only 31 (72%) of 43 barium examinations. Lower oesophageal sphincter (LOS) dysfunction was present in 82% of cases. Using data from medical records and from a survey of gastroenterologists and surgeons in Singapore, the prevalence (in 1996) and incidence of achalasia in Singapore were estimated to be 1.8 per 100000, and 0.3 per 100000 per year, respectively. The incidence was significantly lower in Malays than Chinese or Indians. The age-specific incidence of achalasia for both genders followed a bimodal distribution with the larger peak in the sixth decade. No cases of oesophageal carcinoma were identified among these patients.
  
  
  CONCLUSIONS
  Achalasia is an uncommon condition in Singapore. The clinical and manometric features were similar to those described in Western countries.
authors.affiliation: Department of Medicine, National University of Singapore. mdchoky@nus.edu.sg
authors.forename: K Y
authors.initials: KY
authors.lastname: Ho
authors.forename: H H
authors.initials: HH
authors.lastname: Tay
authors.forename: J Y
authors.initials: JY
authors.lastname: Kang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004931:Esophageal Achalasia / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D004947:Esophagus / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008365:Manometry; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D011859:Radiography; D012846:Singapore / Q000453:epidemiology