Exploring the association between chronic cough and obstructive sleep apnoea in the Kyrgyz Republic

Introduction: Obstructive Sleep Apnoea (OSA) is a type of sleep-disordered breathing that affects 1 billion people worldwide. OSA-patients typically complain from a variety of symptoms, including gasping for air during sleep, frequent awakening and excessive daytime sleepiness. Up to one third of OSA-patients also reported Chronic Cough (CC). The association of CC and OSA in the Kyrgyz Republic (KR) has not been explored yet. Aim: To quantify the prevalence of CC in untreated OSA versus treated OSA. Treatment was defined as Continuous Positive Airway Pressure (CPAP) for more than 4h per night. Methods: All patients with diagnosed OSA who underwent a sleep study at the Sleep Laboratory of the National Hospital for Cardiology and Internal Medicine of Bishkek (KR) between January 2022 and December 2023 were enrolled in the study. We performed a retrospective survey and a telephone interview. We reviewed their demographics, their associated comorbidities and assessed them for CC, defined as a cough lasting more than 8 weeks. Results: A total of 100 patients were diagnosed with OSA between January 2022 and December 2023. 3 of them died and 10 refused to perform the telephone interview; a total of 87 patients were enrolled in the study. Of those 64 (74.6%) males and 23 (26.4%) females, their mean age was 52.1 years, their median Apnea-Hypopnea-Index (AHI) was 25/h. The most common comorbidities were: Obesity (74.7%), Hypertension (52.9%) and Coronary Heart Disease (41.4%). 20 OSA-patients (23%) were treated with CPAP and 67 (77%) remained untreated. The prevalence of CC in the treated group was 10% and in the untreated group was 16.4%. Discussion: Despite its small sample size, this study suggests that the prevalence of chronic cough is higher in untreated versus treated OSA. Patients suffering from CC should therefore be assessed for the presence of OSA and treated accordingly.