Drug therapies for reducing gastric acidity in people with cystic fibrosis.

BACKGROUND

Malabsorption of fat and protein contributes to the poor nutritional status in people with cystic fibrosis. Impaired pancreatic function may also result in increased gastric acidity leading in turn to heartburn, peptic ulcers and the impairment of oral pancreatic replacement therapy. The administration of gastric reducing agents has been used as an adjunct to pancreatic enzyme therapy to improve nutritional status, fat malabsorption and gastro-intestinal symptoms in people with cystic fibrosis. It is thus important to establish the current level of evidence regarding potential benefits of drug therapies that reduce gastric acidity in people with cystic fibrosis.

OBJECTIVES

To assess the effect of drug therapies for reducing gastric acidity: in improving nutritional status; on symptoms associated with increased gastric acidity; fat absorption; lung function; quality of life and survival; and to determine if any adverse effects are associated with their use.

SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group trials register which comprises references identified from comprehensive electronic database searches, handsearching relevant journals and handsearching abstract books and conference proceedings. Most recent search of the Group's register: April 2002.

SELECTION CRITERIA: All randomised and quasi-randomised trials involving agents that reduce gastric acidity compared to placebo or a comparator treatment.

DATA COLLECTION AND ANALYSIS: Both reviewers independently selected trials and assessed trial quality.

MAIN

RESULTS

Thirty-six trials were identified from the initial search. Eleven trials with 172 participants were suitable for inclusion. Five trials were limited to children and three trials enrolled only adults. One trial found that drug therapies which reduce gastric acidity improve gastro-intestinal symptoms such as abdominal pain. Five trials reported significant improvement in measures of fat malabsorption. Two trials reported no significant improvement in nutritional status. Only one trial reported measures of respiratory function and one trial reported an adverse effect with prostaglandin E2 analogue misoprostol. No trials have been identified which assess the effectiveness of agents that reduce gastric acidity in improving quality of life, the complications of increased gastric acidity, or survival.

REVIEWER'S

CONCLUSIONS

Trials have shown limited evidence that the agents which reduce gastric acidity in people with cystic fibrosis are associated with improvement in gastro-intestinal symptoms and fat absorption. Currently, there is insufficient evidence to indicate whether there is an improvement in nutritional status, lung function, quality of life, or survival. We therefore recommend large, multicentre, randomised controlled clinical trials are undertaken to evaluate these interventions.