Introduction
Primary ciliary dyskinesia (PCD), a rare genetic disorder that is characterized by recurrent respiratory infection and pulmonary dysfunction, has historically been viewed as a mild respiratory condition [1]. However, recent data suggest that PCD disease can seriously impair lung function in children of preschool age. In fact, in some children PCD can worsen rapidly and lead to greater decline in lung function during childhood than occurs in pediatric cystic fibrosis (CF) patients [2-4]. Frequent respiratory tract infections appear to be important factor of pulmonary disease progression in PCD patients [5], while also causing repeated hospitalizations that adversely affect quality of life of patients. Moreover, results of one European study revealed that 70% of PCD patients who did not receive regular treatment accumulated more than 50 outpatient visits before diagnosed[6].
Respiratory management of PCD patients is critical in order to prevent irreversible lung damage and appropriate treatment will likely prevent or slow progression of lung damage once a diagnosis is established[5]. Current PCD treatment mainly follows CF and non-CF bronchiectasis treatment recommendations, with azithromycin (AZM) maintenance therapy known to exert beneficial anti-inflammatory effects when use to treat CF and non-CF bronchiectasis [7, 8]. RCTs examining azithromycin versus placebo demonstrated increases of percent predicted forced expiratory volumes (ranged from 2.95% to 6.2%) in AZM-treated CF patients and two studies of azithromycin treatment in adult non-CF bronchiectasis lasting 6 and 12 months showed similar results [9, 10]. For a long time, there were only anecdotal reports of benefit from macrolide antibiotic (Clarithromycin, erythromycin, and azithromycin) in PCD patients[11, 12]. Recently, an international BEAT-PCD consensus statement for infection prevention and control was published in order to improve diagnosis and treatment [13]. Besides, the recently well-designed randomized, placebo-controlled trial showed that significantly improvement of pulmonary exacerbations in PCD patients that received 6-month AZM treatment regimens as compared to those receiving a placebo, while measurements of pulmonary function indicators revealed no significant intergroup differences in changes of predicted FEV1, FVC and FEF25-75 values[14]. Nonetheless, treatment outcomes of pediatric PCD patients receiving AZM are unclear, since studies abovementioned conducted to date have been focused either on adults or included both children and adults.
Here, we describe clinical outcomes of AZM-treated pediatric PCD patients based on longitudinal follow-up periods of 3.1 years on average (4 months to 9.4 years). The aim of the study was to evaluate effects of long term AZM treatment on pulmonary disease status of pediatric PCD patients through retrospective analysis of clinical follow-up data conducted at the largest pediatric pulmonary treatment center in China.