Analysis of the Long-Term Correlates Between Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease: A 10-Year Retrospective Study

Aim This study aims to assess the prevalence of overlap syndrome (OS) in Chronic Obstructive Pulmonary Disease (COPD) patients with Obstructive Sleep Apnea(OSA) symptoms undergoing polysomnography. We investigated the impact of hypoventilation and long-term oxygen therapy (LTOT) on the severity of OSA. Material and Methods We retrospectively reviewed COPD patients with OSA symptoms who underwent polysomnography from August 2012 to September 2022. The individuals' body mass index (BMI), apnea-hypopnea index (AHI), oxygen desaturation index (ODI), minimum and mean oxygen saturation values (minSpO2 and meanSpO2), sleep activities, REM period percentages (REM%), whether they used LTOT, and blood hematocrit levels and awake arterial carbon dioxide (PaCO2) levels were recorded. Results A total of 81 individuals with COPD were included in the study. The number of individuals with AHI>5 was 76(93.9%). Participants included 9 with mild OSA, 24 with moderate OSA and 43 with severe OSA. The mean sleep efficiency was found to be %78.3. The mean value of REM% was 7.3. Sixteen of the patients (19.7%) were receiving LTOT. Sleep efficiency was statistically higher in the group using LTOT (p=0.048). AHI and ODI values were statistically higher in the group with high PaCO2 than in the group without (respectively; p=0.048, p=0.008). The mean values of min SpO2 and meanSpO2 were found to be lower in the group with high PaCO2 (p=0.013, p=0.008; respectively) Conclusion In OS participants, sleep efficiency is low, and having high PaCO2 is associated with lower minSpO2 and meanSpO2, higher ODI, and AHI. The use of LTOT increases sleep efficiency.