Inhaling concentrated saline (salt water) mist does not reduce how often infants and young children with cystic fibrosis (CF) need antibiotics for respiratory symptoms, according to findings from a clinical trial sponsored by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health. This trial is the largest study of concentrated, or hypertonic, saline therapy in infants and preschoolers.

Previous findings have shown that hypertonic saline provides some benefits to adults and older children with CF. The saline mist appears to loosen the thick mucus that builds up in the lungs and may reduce the recurrent infections, known as pulmonary exacerbations, which are thought to contribute to the lung damage and respiratory failure associated with CF. Based on these 2006 findings, the use of hypertonic saline in younger children has been rising. About 1 in 5 children under 6 years old with CF currently use this therapy, but without any clear evidence that it is effective in these children.

“Even reasonably simple and non-toxic therapies can be burdensome, especially for families of small children with a chronic disease such as cystic fibrosis,” said Susan Shurin, MD, acting director of the NHLBI, and a paediatrician. “This is one more study that illustrates the importance of conducting clinical research in children because medicine is not one size fits all — therapies that benefit adults or even teenagers do not always benefit younger children in the same way.”

Results of the Infant Study of Inhaled Saline (ISIS) clinical trial will be published online May 20 in the Journal of the American Medical Association. The findings will be presented on the same date at the American Thoracic Society Annual Meeting in San Francisco.

This paediatric study of hypertonic saline therapy enrolled 321 participants aged 4 months to 60 months at 30 CF care centres across the United States and Canada. The participants inhaled either 7 per cent hypertonic saline, or a 0.9 per cent saline mist as a control, twice daily for 48 weeks.

Overall, the hypertonic saline was well-tolerated and side effects were minimal. However, there was no difference between the two saline groups in the rate of acute lung problems that required treatment with antibiotics (average of 2.3 cases per participant per year in each group). Hypertonic saline also did not improve other clinical measurements such as coughing, respiratory rate, height, or weight. CF can stunt the growth of children.

The study authors noted that CF complications in infants and young children generally have different origins than complications in adults and older children; for instance, young children develop more viral, as opposed to bacterial, infections. These differences in complications might account for the lack of effectiveness of the hypertonic saline in reducing antibiotic use in children.

Early lung damage associated with CF frequently shows no clinical symptoms. Whether hypertonic saline treatment in infants and young children could still slow the progression of airway damage, resulting in better lung function later, is not known.

CF is an inherited disorder that results in a buildup of thick and sticky mucus in the lungs, airway, and other organs. The excess mucus in the lungs can lead to coughing, breathing problems, and increased risk of lung infections. There is no cure, although advances in treatments have improved both the length and quality of life of people with this disease.

This study was supported by NIH grants U01HL092931, U01HL092932, and UL1RR025014. Additional support was provided by The Cystic Fibrosis Foundation Therapeutics, Inc.; study drug and control were supplied by Pari Respiratory and Catalent, respectively.

Part of the NIH, NHLBI plans, conducts, and supports research related to the causes, prevention, diagnosis, and treatment of heart, blood vessel, lung, and blood diseases; and sleep disorders. The Institute also administers national health education campaigns on women and heart disease, healthy weight for children, and other topics.

NIH, the nation's medical research agency, and is a component of the US Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases.