Interstitial lung disease and gastroesophageal reflux disease: key role of esophageal function tests in the diagnosis and treatment.

CONTEXT: Gastroesophageal reflux disease (GERD) is common in patients with respiratory disorders and interstitial lung fibrosis from diverse disease processes. However, a cause-effect relationship has not been well demonstrated. It is hypothesized that there might be more than a coincidental association between GERD and interstitial lung damage. There is still confusion about the diagnostic steps necessary to confirm the presence of GERD, and about the role of effective control of GERD in the natural history of these respiratory disorders.
OBJECTIVES: To determine the prevalence of GERD in patients with respiratory disorders and lung involvement; the sensitivity of symptoms in the diagnosis of GERD; and the role of esophageal function tests (manometry and 24- hour pH monitoring) in the diagnosis and treatment of these patients.
METHODS: Prospective study based on a database of 44 patients (29 females) with respiratory disorders: 16 patients had idiopathic pulmonary fibrosis, 11 patients had systemic sclerosis associated interstitial lung disease, 2 patients had polymyositis associated interstitial lung disease, 2 patients had Sjögren associated interstitial lung disease, 2 patients had rheumatoid artrithis associated interstitial lung disease, 1 patient had undifferentiated connective tissue diseases associated interstitial lung disease and 10 patients had sarcoidosis. The average forced vital capacity (% predicted) was 64.3%. All patients had esophageal function tests.
RESULTS: Thirty patients (68%) had pathologic reflux (average DeMeester score: 45, normal <14.7). The average number of reflux episodes recorded 20 cm above the lower esophageal sphincter was 24. Sensitivity and specificity of heartburn were 70% and 57%, of regurgitation 43% and 57%, and of dysphagia 33% and 64%. Twelve patients with GERD underwent a laparoscopic fundoplication which was tailored to the manometric profile: three patients in which peristalsis was normal had a total fundoplication (360°) and nine patients in which the peristalsis was absent had a partial anterior fundoplication (180°).
CONCLUSIONS: The results of our study show that: (a) abnormal reflux was present in about 2/3 of patients with respiratory disorders (idiophatic pulmonary fibrosis, connective tissue disorders and sarcoidosis), and it extended to the upper esophagus in most patients; (b) the sensitivity and specificity of reflux symptoms was very low; and (c) esophageal function tests were essential to establish the diagnosis of abnormal reflux, to characterize the esophageal function and guide therapy. Long term follow-up will be necessary to determine if control of reflux alters the natural history of these respiratory disorders.