Characteristics of gastro-esophageal reflux in patients with idiopathic pulmonary fibrosis

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BackgroundIdiopathic pulmonary fibrosis (IPF) is a chronic fibrotic lung disease with a median survival rate ranging from 2 to 3years from diagnosis. Recent data have illustrated the role of gastro-esophageal reflux (GER) in the pathogenesis and potential management of IPF patients. Although it is recognized that GER is increased among IPF patients, its prevalence and characteristics had been poorly defined. Patients and methodsForty patients were recruited; 20 with a diagnosis of IPF and the other, 20 with interstitial lung disease other than IPF (non IPF patients). All patients underwent pulmonary high-resolution computed tomography (HRCT) scan and impedance-pH monitoring while off antisecretory therapy. The presence of pulmonary fibrosis was assessed using validated HRCT scores. Reflux features included distal esophageal acid exposure, number of acid/weakly acidic reflux episodes and their proximal migration. ResultsSeventeen (85%) patients out of 20 with IPF had an abnormal distal acid exposure, compared with 7 (35%) out of 20 non IPF patients (p=0.003). Percentage total acid exposure time (AET) with pH<4 was significantly higher in IPF compared with non IPF patients (median (range) 10.1 (5.1–16.3) versus 3 (1.2–8.3), respectively; p<0.0001). In IPF patients the total (both acid and weakly acidic) numbers of reflux episodes [80 (45–99)], acid reflux [46 (25–57)] and weakly acidic reflux [35 (20–45)] were significantly higher than those of non IPF patients (45 (29–70), 28 (18–40) and 19 (10–30), respectively; p<0.0001). Also, more reflux episodes reached the proximal esophagus [54 (28–69)] in IPF patients than non-IPF patients [18 (8–32); p<0.0001]. In IPF patients there was a significant positive correlation between degree of pulmonary fibrosis (HRCT score) and total number of reflux episodes in both the distal (r2=0.57, p=0.008) and proximal (r2=0.61, p=0.004) esophagus. In contrast, in non IPF patients a non significant correlation was found between degree of pulmonary fibrosis and total number of reflux episodes in both the distal (r2=0.17, p=0.48) and proximal (r2=0.23, p=0.34) esophagus. ConclusionIPF patients have greater GER rate compared to non IPF ones. Not only acid reflux, but also weakly acidic reflux is significantly increased among IPF patients.