Undiagnosed Sleep Disordered Breathing May Significantly Impacts Outcome in Hospitalized Patients Admitted for COPD in an Inner City

Abstract

Background: COPD is the second most common cause of hospital admission in the United States. Sleep Disordered Breathing is a highly prevalent and under-diagnosed condition which may impact the outcome of COPD. We hypothesized that the presence of unrecognized and untreated SDB will increase hospital readmissions in patients admitted for COPD exacerbation. Methods: We reviewed consecutive patients admitted for COPD exacerbation from Nov 2016 - October 2017 who were also screened for SDB with sleep questionnaire, and who subsequently underwent a high-resolution pulse-oximetry (HRPO) or portable sleep monitoring (PM). We compared the rates of 30, 60 and 90-day readmission or death across SDB categories and compared overall survival in patients with and without SDB. Results: Of the total of 380 patients admitted for COPD exacerbation, 256 were screened for SDB with a sleep questionnaire (STOP). Of these, 238 underwent an overnight HRPO/PM. Out of the total of 238 patients, 111 (46.6%) were found to have SDB; 28.6% had mild, 9.7% moderate and 8.4% severe SDB. Baseline characteristics and demographics were compared for COPD- SDB and COPD- no SDB and were similar, except patients with SDB who had an increased mean BMI (33.9 vs 30.3) and increased co-morbidity of heart failure (19.8% vs 7.1%). Among patients with COPD-SDB the odds of 30-day readmission were 3.5 times as high as for COPD- no SDB patients (45% vs 19%, P < .001). Additionally, the odds of readmission were 3.3 as high for moderate SDB patients than mild SDB patients (61% vs 32%) and 1.5 times as high for severe SDB patients than moderate SDB patients (70% vs. 61%). The overall survival time was lower for patients with SDB than patients with no SDB (P = .001). The time to hospital readmission or death increased with increasing SDB severity (P < .001). Conclusions: Patients admitted to the hospital for COPD exacerbations have significant burden of undiagnosed SDB, which may a significantly impact 30-day readmission rate. Longer term follow-up shows worse outcome with the composite endpoint of readmissions and death.