Changes in Prescription Patterns and Diagnostic Outcomes of Polysomnography After Insurance Coverage: A Multicenter Retrospective Study

Background and Objectives: In June 2018, South Korea expanded insurance coverage for polysomnography (PSG) to improve diagnostic access for obstructive sleep apnea (OSA). This study investigated the impact of this policy by analyzing changes in PSG utilization and diagnostic outcomes. Methods: A multicenter retrospective study was conducted using data from 17 tertiary hospitals across South Korea. Patients aged ≥20 years who visited the hospitals for suspected OSA between 2015 and 2023 were included. The pre-coverage period was defined as 2015–2017, and the post-coverage period as 2019–2023. Demographics, PSG implementation rates, and apnea-hypopnea index (AHI) distributions were compared. Results: A total of 29,055 patients were included (7,800 pre-coverage; 21,255 post-coverage). PSG utilization significantly increased from 51.3% to 74.4% (p<0.001). The proportion of female patients rose from 20.0% to 23.0%, and the mean age increased from 45.8 to 49.8 years (p<0.001). The average AHI increased from 31.2 to 35.3. The proportion of patients with severe OSA (AHI ≥30) rose from 42.8% to 48.8%, while cases with normal AHI (<5) declined from 11.6% to 8.3% (p<0.001). Conclusion: The expansion of insurance coverage significantly improved PSG accessibility, particularly for older adults, women, and high-risk patients. The observed shift toward more severe diagnoses suggests enhanced detection of untreated OSA rather than overdiagnosis of mild or normal cases. These findings support the ongoing implementation of inclusive health policies while emphasizing the importance of appropriate patient selection.