by Margaret Rosenfeld, MD, MPH
Dr. Rosenfeld, from Seattle Children's Hospital, provides insight into her study on hypertonic saline in children younger than 6 years old with cystic fibrosis. Her research was presented at the American Thoracic Society 2012 International Conference and appeared in the June 6 JAMA. Also, see our article on the topic published in the July issue of Pulmonary Reviews.
We performed a multicenter, randomized, double-blind, placebo-controlled trial of 7% hypertonic saline versus isotonic saline in 321 patients with cystic fibrosis (CF) who were younger than 6 years old.
This is the first study to evaluate a non-antibiotic therapy in children with CF in this young age group, and speaks to the ability of this type of study to be done in the future in young children with CF. We know that studying potential therapies before age 6 is important because therapies in this age group might be able to prevent lung damage from occurring, rather than treat lung damage that is already irreversible.
Unfortunately, hypertonic saline did not have any effects on the primary or secondary outcome measures, which included pulmonary exacerbation rates and measures of respiratory symptoms. As eloquently stated in the editorial accompanying our study in JAMA, other potential endpoints may need to be considered in this age group, such as imaging with CT scan or lung clearance index.
Our study also had a subgroup of participants in whom infant lung function testing was performed. There was a small difference in the forced expiratory volume in 0.5 seconds, which was 38 mL. However, more than one-third of the participants did not have two acceptable measurements, which could have introduced bias. Further, this change might not be a clinically important difference in the real world.
At this point, there is no evidence that initiating treatment with 7% hypertonic saline in CF patients younger than 6 years would be beneficial in terms of pulmonary exacerbation rates, height, weight, respiratory rate, oxygen saturation, cough, or respiratory symptom score. Therefore, this treatment should be reserved for those CF patients older than 6 until more evidence is available. Hopefully, different endpoints that look at progression, rather than treatment, of existing disease can be found to assess whether hypertonic saline have any benefit in these young CF patients.