Obstructive Sleep Apnea in Patients With Non-UIP Idiopathic Interstitial Pneumonia

Abstract

PURPOSE: A high prevalence of obstructive sleep apnea (OSA) has been found in patients with idiopathic pulmonary fibrosis (IPF).Patients with idiopathic interstitial pneumonias (IIPs) other than IPF present clinically and radiologically similar to IPF. No clinical literature on the prevalence and impact of sleep-disordered breathing exists in non-IPF IIPs. METHODS: A retrospective analysis of patients with non-IPF IIPs seen at Utah Valley Pulmonary Clinic was carried out. Medical records were reviewed for IIP diagnosis, mode of diagnosis, duration of illness, presence of concomitant sleep apnea, duration of therapy with continuous positive airway pressure (CPAP) and progression of pulmonary function test (PFT) abnormalities. Analysis was confined to patients accorded a diagnosis of either non-specific interstitial pneumonia (NSIP) or chronic hypersensitivity pneumonitis (HSP). Pathologic and/or radiologic confirmation of NSIP or HSP diagnosis was done by a pathologist and chest radiologist experienced in interstitial lung disease. RESULTS: 10 patients were encountered with either a biopsy-confirmed diagnosis of NSIP (4), biopsy-confirmed HSP (1), radiologically-interpreted NSIP (4), and radiologically-interpreted HSP (1). 9/10 patients were females. Ages ranged from 36-81 years. All patients were non-smokers. Duration of IIP diagnosis ranged from 1-11 years. 5 patients were treated with immunosuppressive agents following exacerbations of their underlying disease (4/5) or for worsening lung function (1/5). Patients were treated with prednisone during the acute phase followed by maintenance therapy with azathioprine (3/5) and mycophenolate (2/5). On polysomnography (PSG), 7/8 patients demonstrated abnormal apneahypopnea indices (range 7-56.5); 1/8 showed sleep-related hypoxemia. 1 patient refused evaluation for OSA despite high clinical suspicion of OSA and another had multiple optimal overnight oximetries without any clinical features of sleepdisordered breathing. 4 patients experienced exacerbations prior to initiation of OSA therapy with one experiencing recurrent NSIP exacerbations. On serial PFTs, stability in forced vital capacity values was noted in the majority of patients compliant with CPAP therapy. CONCLUSIONS: A high prevalence of obstructive sleep apnea exists in patients with non-IPF IIPs. CLINICAL IMPLICATIONS: Screening and aggressive management of concomitant OSA with CPAP may help with stabilization of lung function in patients with non- UIP IIPs and prevention of NSIP/HSP exacerbations.