title: Prevalence of gastroesophageal reflux in difficult asthma: relationship to asthma outcome.
abstract: OBJECTIVE
  To determine the prevalence of gastroesophageal reflux disease (GERD)-both symptoms and objective evidence-using 24-h dual-probe pH monitoring in difficult asthma, and the relationship between the presence and treatment of GERD to clinical outcome.
  
  
  METHODS
  As part of a systematic evaluation protocol, 68 subjects with difficult-to-control asthma attending a difficult asthma clinic were referred for dual-probe ambulatory pH esophageal monitoring.
  
  
  RESULTS
  Esophageal probe data were available in 52 patients (76%) with difficult asthma. The prevalence of GERD/GERD-associated asthma symptoms was 75% (39 of 52 patients; 95% confidence interval [CI], 63 to 84.7%). The prevalence of GERD as evidenced by an abnormal pH profile at the distal esophageal probe was 55% (29 of 52 patients; 95% CI, 40 to 69%). The prevalence of GERD at the proximal probe was 34.6% (18 of 52 patients; 95% CI, 23.6 to 51%). The prevalence of GERD was similar in asthmatic subjects who responded to intervention and those who remained difficult to control (therapy resistant). Asymptomatic GERD was present in 9.6% (5 of 52 patients); 16% of cough episodes correlated with acid reflux.
  
  
  CONCLUSIONS
  In difficult-to-control asthma, GERD is common, but identification and treatment of GERD do not appear to relate to improvement in asthma control in this population.
authors.affiliation: Regional Respiratory Centre, Level 8, Belfast City Hospital, Lisburn Rd, Belfast, BT97AB, UK.
authors.forename: Julian J
authors.initials: JJ
authors.lastname: Leggett
authors.forename: Brian T
authors.initials: BT
authors.lastname: Johnston
authors.forename: Moyra
authors.initials: M
authors.lastname: Mills
authors.forename: Jackie
authors.initials: J
authors.lastname: Gamble
authors.forename: Liam G
authors.initials: LG
authors.lastname: Heaney
mesh_terms: D000328:Adult; D001249:Asthma / Q000150:complications* / Q000188:drug therapy; D005260:Female; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D008297:Male; D015995:Prevalence; D017211:Treatment Failure