1. Zhao, Sai MMed

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This article is a summary/review of the below article:


Ng, S. M., & Franchini, A. J. (2014). Drug therapies for reducing gastric acidity in people with cystic fibrosis. Cochrane Database of Systematic Reviews, (7), CD003424. Retrieved from



Cystic fibrosis (CF) is a chronic and progressive inherent disease of the body's exocrine glands. It occurs more frequently in the Caucasian population. According to the data collected by Cystic Fibrosis Foundation (2012), there are approximately 30,000 people with CF in the United States and an estimated 70,000 people with CF worldwide.


Cystic fibrosis affects the secretion of exocrine glands distributed in various organs of the body such as the lungs and pancreas. A majority of people with CF suffer from exocrine pancreatic insufficiency, which induces acid stomach and malabsorption of fat and protein. Fat and protein are two primary macronutrients performing essential roles in the human body, such as providing energy and maintaining and repairing body tissues. In addition, these proteins are involved in the immune process. The consistent loss of these two nutrients can consequently lead to growth defects, increase the likelihood of pulmonary disease, and ultimately shorten a person's life span (Kraemer, Ruderberg, Hodorn, & Rossi, 1978; Murphy, Wooton, Bond, & Jackson, 1991).


Oral supplements of pancreatic enzymes have been used to improve the nutritional status induced by pancreatic insufficiency in people with CF. However, the effect of pancreatic replacement can be limited, which may be due to the hyperacidity in the stomach, as the pancreatic enzymes may be inactivated by gastric acid. Therefore, other agents that reduce gastric acidity are suggested as an additional therapy to prevent the fat malnutrition (DiMagno, 2001). The current Cochrane review evaluates the effect of adjuvant drug therapy on reducing gastric acidity in people with CF receiving pancreatic enzyme therapy (Ng & Franchini, 2014).



To test the hypotheses that in people with CF, agents that reduce gastric acidity:


* improve nutritional status, as assessed by weight, height, and other indices of growth;


* alleviate symptoms associated with increased gastric acidity such as heartburn and epigastric pain;


* improve lung function, quality of life, and survival; and


* do not have unacceptable adverse effects.



The Cochrane review includes 17 relevant trials with 273 participants, 14 of which were crossover randomized trials and only three randomized trials were of parallel design. The participants were both children (n = 218) and adults (n = 55). All included trials had very small sample sizes, from 6 to 38 participants.


The review compared four active therapies with placebo: pump inhibitors (six randomized controlled trials [RCTs], n = 47 adults and n = 30 children), H2 receptor antagonist (seven RCTs, n = 120 children), prostaglandin E2 analogue misoprostol (one RCT, n = 17 children), and sodium bicarbonate (one trial, n = 22 children). Three small trials investigated the difference between two different active therapies. One trial (n = 22 children) compared the normal dose pancrease and prostaglandin E2 analogue misoprostol (100 [mu]g every 6 hours) with the normal dose pancrease alone. One trial (n = 8 adults) compared H2 receptor antagonist (ranitidine) with prostaglandin E2 analogue (enprostil). The other trial (n = 22 children) compared sodium bicarbonate with calcium carbonate. Treatment duration ranged from 5 days to 12 months. The types of pump inhibitor assessed in the Cochrane review were omeprazole and esomeprazole, either used alone or combined with pancrelipase. The assessed H2 receptor antagonists in the review were ranitidine, cimetidine, or famotidine.



Meta-analysis was not performed because of the variation in study design. The included trials were generally not reported adequately enough to allow judgments on risk of bias.


However, two trials comparing an H2 receptor antagonist with a placebo reported no significant improvement in height, weight, and skinfold thickness between the treatment and control groups. Body mass index and z scores for weight and height were not reported in either trial. One trial found that drug therapies (misoprostol) that reduce gastric acidity alleviated gastrointestinal symptoms such as abdominal pain. No trials have been identified assessing the effectiveness of these agents in reducing the complications of increased gastric acidity.



The review authors concluded that limited evidence demonstrated that adjuvant agents reducing gastric acidity are "associated with improvement in gastrointestinal symptoms" (Ng & Franchini, 2014). Actually, this conclusion is based on the results from two RCTs comparing H2 receptor antagonist with a placebo in children with CF.


The other conclusion of the review is that there is insufficient evidence to indicate whether the assessed agents can improve nutritional status. The authors also suggested undertaking multicenter RCTs with large sample sizes. It should be noted that there is also a lack of evidence assessing the effectiveness of these agents in reducing the complications of gastric hyperacidity such as gastric or duodenal ulcers. To identify the effects of the agents on complications, large observational studies may be more effective than RCTs.


Implications for Practice

In a clinical scenario, nurses usually act as healthcare provider, advocate, and educator for patients with CF. DiCenso, Guyatt, and Ciliska (2005) suggest a three-step approach to help nurses use the literature evidence to solve clinical problems: (i) Are the results valid? (ii) What are the results? and (iii) How can I apply the results to patient care? Therefore, we will consider the review in light of these three steps.


First, nurses should note that the quality of the current evidence is very weak due to the sparse data; this may affect the validity and confidence of the main findings of the Cochrane review (Ng & Franchini, 2014). Second, the results of the systematic review demonstrated that agents reducing gastric acidity may benefit children (younger than 18 years) with CF in alleviating gastrointestinal symptoms; the effect size, however, remains unclear. This positive effect was observed after a long-term use of cimetidine; the reported treatment durations were 4 and 12 months. It remains unclear whether the assessed agents can improve nutritional status and reduce complications of increased gastric acidity. The last, but not the least, step is to consider the applicability of the evidence-whether the population and interventions described in the body of evidence conform to the characteristics of our patients in the real world. Nurses need to consider or provide suggestions on whether the beneficial effects demonstrated by the systematic review can also be achieved by patients.




Cystic Fibrosis Foundation. (2012). Annual data report. National Patient Registry. Retrieved from


DiCenso A., Guyatt G., Ciliska D. (2005). Evidence-based nursing: A guide to clinical practice. St. Louis, MO: Elsevier Mosby. [Context Link]


DiMagno E. P. (2001). Gastric acid suppression and treatment of severe pancreatic exocrine insufficiency. Best Practice and Research in Clinical Gastroenterology, 15(3), 477-486. [Context Link]


Kraemer R., Ruderberg A., Hodorn B., Rossi E. (1978). Relative underweight in cystic fibrosis and its prognostic value. Acta Paediatrica Scandinavica, 67(1), 33-37. [Context Link]


Murphy J. L., Wooton S. A., Bond S. A., Jackson A. A. (1991). Energy content of stools in normal healthy controls and patients with cystic fibrosis. Archives of Disease in Childhood, 66(4), 495-500. [Context Link]


Ng S. M., Franchini A. J. (2014). Drug therapies for reducing gastric acidity in people with cystic fibrosis. Cochrane Database of Systematic Reviews, (7), CD003424. Retrieved from[Context Link]