PURPOSE: Studies suggest a high proportion of ILD patients have OSA or GERD. To our knowledge, no investigator has examined both together in patients with ILD. There is speculation that GERD (or more precisely, occult micro-aspiration) lies within the causal pathway of ILD; however, a competing hypothesis holds that ILD alters lower esophageal function and increases the likelihood of GERD. We hypothesized that OSA and GERD would be common in fILD and that the majority of patients with GERD would have OSA.
METHODS: Subjects included patients with non-connective tissue disease-related fILD evaluated at our center from 2006-2010. Sleep studies (PSG) and pH probes were performed as part of the clinical evaluation for ILD, and 45 of 55 subjects had them pre-ordered without regard—and prior—to symptom assessment by the evaluating physician. OSA was present if apnea-hypopnea index exceeded 5; GERD if the proximal channel pH < 4 for ≥ 0.9% total time, ≥ 1.2% upright time, or > 0% recumbent time; or if the distal channel pH was < 4 for ≥ 4.2% total time (non-medicated or ≥ 1.3% total time if medicated), ≥ 6.3% of the upright time (non-medicated or ≥ 1.5% upright time if medicated), or ≥ 1.2% of the recumbent time (non-medicated or ≥ 1.3% recumbent time if medicated).
RESULTS: The most prevalent diagnosis was idiopathic pulmonary fibrosis (n=23). Of 55 subjects, 15 had OSA, 17 had GERD, 21 had both; only 2 subjects had neither. The group with OSA only had a mean BMI of 34.2; those with GERD had a BMI= 30; and those with both had a BMI=29. Lung function did not discriminate between subgroups.
CONCLUSIONS: There is a high prevalence of OSA and GERD in fILD patients.
CLINICAL IMPLICATIONS: PSG and pH probe should be considered in the routuine evaluation of ILD patients. However, the cause of the high prevalence of these conditions; the clinical implications of their presence in fILD patients; and determining whether treating these comorbid conditions will alter outcomes in this patient group requires further exploration.
DISCLOSURE: The following authors have nothing to disclose: Manju Pillai, Teofilo Lee-Chiong, Philip Hanna, Jeff Swigris
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