Does medical antireflux therapy improve asthma in asthmatics with gastroesophageal reflux? A critical review of the literature

Objective: Identify and critically review the peer-reviewed, English-language studies of the effects of medical antireflux therapy in asthmatics with gastroesophageal reflux (GER). Design: Using the 1966 to 1996 MEDLINE database, asthma was combined with GER to identify all studies of the effects of medical antireflux therapy on asthma control. The articles' bibliographies were also reviewed. Studies were graded according to Sackett's criteria and grouped by levels of evidence. Results: A total of 242 citations were found; 171 were published in English. Twelve studies of the effects of medical antireflux therapy on asthma control, with a total of 326 treated patients, were identified. Eight studies were placebo-controlled, three were open studies, and one used an untreated control. Eight studies treated 20 or fewer patients. Reflux symptoms either did not improve or the effects of antireflux therapy on them were not reported in four studies. The combined data from the controlled medical antireflux studies showed that: (1) asthma symptoms improved in 69% of the subjects; (2) asthma medication usf, was reduced in 62% of the subjects; (3) evening peak expiratory flow (PEF), but not PEF at other times, improved in 26% of the subjects; and (4) spirometry did not improve in any of the placebo-controlled antireflux studies. Conclusions: Analysis of the combined data suggests that medical antireflux therapy improves asthma symptoms, may reduce asthma medication use, but has minimal or no effect on lung function.