Cough in association with gastroesophageal reflux disease (GORD) is common in adults with chronic cough. The objective of this review was to evaluate the effectiveness of GORD treatment in children and adults with GORD and prolonged cough that is not related to an underlying respiratory disease, i.e. non-specific chronic cough.
Nineteen studies fulfilled our predetermined criteria but only six could be combined (in meta-analysis). We obtained additional data from trialists. We were not able to combine results in children due to limited data. Thickened feeds had an inconsistent effect. Proton pump inhibitors (PPI) did not reduce cough and should not be used for cough in young children.
In adults with cough and GORD, no significant difference was found in clinical cure using proton pump inhibitors (PPI) for cough and GORD. Using other outcomes, there was also no significant difference between PPI and placebo. This review also highlights a large placebo and time period effect (natural resolution with time) of treatment for chronic cough. In adults treatment with PPI for cough associated with GORD is inconsistent and its benefit variable. There was insufficient data to draw any conclusion from other therapies for cough associated with GORD.
PPI is not efficacious for cough associated with GORD symptoms in very young children (including infants) and should not be used for cough outcomes. There is insufficient data in older children to draw any valid conclusions. In adults, there is insufficient evidence to conclude definitely that GORD treatment with PPI is universally beneficial for cough associated with GORD. Clinicians should be cognisant of the period (natural resolution with time) and placebo effect in studies that utilise cough as an outcome measure. Future paediatric and adult studies should be double-blind, randomised controlled and parallel-design, using treatments for at least two months, with validated subjective and objective cough outcomes and include ascertainment of time to respond as well as assessment of acid and/or non-acid reflux.
Gastroesophageal reflux disease (GORD) is said to be the causative factor in up to 41% of adults with chronic cough. Treatment for GORD includes conservative measures (diet manipulation), pharmaceutical therapy (motility or prokinetic agents, H2-antagonist and proton pump inhibitors (PPI)) and fundoplication.
To evaluate the efficacy of GORD treatment on chronic cough in children and adults with GORD and prolonged cough that is not related to an underlying respiratory disease, i.e. non-specific chronic cough.
We searched the Cochrane Airways Group Specialised Register, the Cochrane Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, review articles and reference lists of relevant articles. The date of last search was 8 April 2010.
All randomised controlled trials (RCTs) on GORD treatment for cough in children and adults without primary lung disease.
Two review authors independently assessed trial quality and extracted data. We contacted study authors for further information.
We included 19 studies (six paediatric, 13 adults). None of the paediatric studies could be combined for meta-analysis. A single RCT in infants found that PPI (compared to placebo) was not efficacious for cough outcomes (favouring placebo OR 1.61; 95% CI 0.57 to 4.55) but those on PPI had significantly increased adverse events (OR 5.56; 95% CI 1.18 to 26.25) (number needed to treat for harm in four weeks was 11 (95% CI 3 to 232)). In adults, analysis of H2 antagonist, motility agents and conservative treatment for GORD was not possible (lack of data) and there were no controlled studies of fundoplication. We analysed nine adult studies comparing PPI (two to three months) to placebo for various outcomes in the meta-analysis. Using intention-to-treat, pooled data from studies resulted in no significant difference between treatment and placebo in total resolution of cough (OR 0.46; 95% CI 0.19 to 1.15). Pooled data revealed no overall significant improvement in cough outcomes (end of trial or change in cough scores). We only found significant differences in sensitivity analyses. We found a significant improvement in change of cough scores at end of intervention (two to three months) in those receiving PPI (standardised mean difference -0.41; 95% CI -0.75 to -0.07) using generic inverse variance analysis on cross-over trials. Two studies reported improvement in cough after five days to two weeks of treatment.