1. Introduction
Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in CFTR , a gene that encodes a chloride and bicarbonate channel.1 Loss of CFTR function results in abnormal mucus in the respiratory tract.2,3 Because patients with CF have defects in mucociliary transport,2,4 CF care guidelines recommend physical methods of airway clearance starting at an early age.5 Several airway clearance methods are routinely used in CF, including huff coughing, oscillating positive expiratory pressure devices (PEP), high frequency chest wall oscillation (vest), and aerobic or resistance exercise training.6,7 Several studies have found no evidence that any specific airway clearance technique is superior to another,8,9 although people with CF may prefer certain forms of airway clearance depending on age, developmental status, or disease progression. Some studies also report differences between males and females in airway clearance practices.7
While airway clearance treatments are almost universally prescribed, they can be challenging for patients and families across the age spectrum. Barriers to completing airway clearance may include time commitment, lack of financial resources, perceived lack of effectiveness, and discomfort. While care teams may recommend up to two hours per day of airway clearance, actual use of these methods is often far less than prescribed.10-12 Completing airway clearance becomes increasingly difficult as children age12 and are prescribed other therapies due to disease progression. The teenage years are a time of low adherence to airway clearance.10 Teens manage their CF while maintaining busy academic, social, and extracurricular schedules with progressively less parental supervision. Historically, this correlates with a period of worsening lung function and increased hospitalizations.13 Additionally, socioeconomic factors significantly impact the ability to complete airway clearance. Families with maternal college education, annual income >$50,000, and more adults in the household have higher completion of airway clearance.10 Airway clearance may be painful or unpleasant for some patients. In hospitalized patients at our center, we routinely observe refusal to complete physical therapy and other forms of airway clearance due to lack of energy, fatigue, shortness of breath, coughing, skin irritation, pain, or discomfort. Furthermore, the effectiveness of some methods of airway clearance has been questioned, particularly if not performed correctly.14
The role of airway clearance for patients with CF could change with the introduction of CFTR modulator drugs.15-19 These medications increase the activity of endogenous CFTR and cause immediate improvements in mucociliary transport,20 pulmonary air trapping,21 and lung function.15-19This raises questions about the future role or need for airway clearance in people with CF following initiation of highly effective CFTR modulator drugs. Surveys of patients using CFTR modulators show that most (292/359, 81%) have not discontinued chronic treatments, although respondents ranked airway clearance techniques as their most burdensome treatment.22
To assess usage of airway clearance, identify barriers to regular use, and understand why some methods of airway clearance are preferred over others, we administered an anonymous survey to patients and caregivers in our pediatric and adult CF center. We hypothesized that adolescent patients (patients ages 10-19 years) would report less time using airway clearance methods compared to adults or younger children, and that patients would prefer forms of airway clearance that are convenient or coordinate better with other therapies. Additionally, we hypothesized that many forms of airway clearance are not completed because they are painful, unpleasant, or poorly tolerated. We considered that male and female patients could use different forms of airway clearance during adolescence and experience side effects differently. Finally, we predicted that patients taking CFTR modulators would report less airway clearance because of improved health.