Obstructive sleep apnea (OSA) and chronic insomnia are two common sleep disorders and both are considered independent risk factors for heart disease. The aim of this study was to investigate the prevalence of comorbid insomnia with OSA and to compare its clinical characteristics with those of OSA without insomnia. Patients who visited two tertiary university hospital sleep centers were screened. Those with a diagnosis of OSA using polysomnography were divided into two groups based on their scores on the Korean version of the Insomnia Severity Index (ISI-K): OSA with insomnia (OSA+I) (ISI-K score ≥ 15) and OSA without insomnia (OSA−I) (ISI-K score < 15). Subjective symptoms were evaluated using sleep questionnaires including ISI-K. Demographic and clinical characteristics of OSA+I and OSA−I were compared. Out of 476 patients with OSA, 139 (29.2%) had significant insomnia. Patients in the OSA+I group had a higher percentage of females (35.3% versus 19.6%, P < .001) and have higher rates of heart disease (19.4% versus 8.6%, P < .001). OSA+I group showed lower quality of life, lower quality of sleep, higher sleep propensity, and higher depression as measured by the Korean versions of the Short-Form 36-Item Health Survey, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and Beck Depression Inventory, respectively. There were no significant differences in adherence to continuous positive airway pressure between the groups. There is a high prevalence of comorbid insomnia with OSA (29.2%), consistent with previous findings in Western studies. Comorbid insomnia with OSA may constitute a cumulative risk factor for cardiovascular disease. These findings warrant further investigation into the mechanisms involved in its pathogenesis and devising more efficient treatments. Cho YW, Kim KT, Moon H, Korostyshevskiy VR, Motamedi GK, Yang KI. Comorbid insomnia with obstructive sleep apnea: clinical characteristics and risk factors. J Clin Sleep Med. 2018;14(3):409–417.

To determine the prevalence, sleep characteristics, and comorbidities associated with a high risk for obstructive sleep apnea (OSA) in the Korean adult population. We analyzed data from 2,740 subjects who responded to a nationwide questionnaire survey of sleep characteristics. Those who qualified under two or more symptom categories of the Berlin questionnaire were defined as “at high risk for OSA”. We investigated their socio-demographic information, sleep habits, and medical and psychiatric comorbidities. Logistic regression analyses were performed to identify factors and consequences significantly associated with a high risk for OSA. The prevalence of a high risk for OSA was 15.8% (95% confidence interval [CI] 14.5–17.2%). Multiple logistic regression analysis showed that old age (≥ 70 years, odds ratio [OR] 2.68) and body mass index ≥ 25 kg/m² (OR 10.75) were significantly related with a high risk for OSA, whereas regular physical activity (OR 0.70) had a protective effect. Subjective sleep characteristics associated with a high risk for OSA were perceived insufficient sleep (OR 1.49), excessive daytime sleepiness (OR 1.88), and insomnia (OR 3.70). In addition, hypertension (OR 5.83), diabetes mellitus (OR 2.54), hyperlipidemia (OR 2.85), and anxiety (OR 1.63) were comorbid conditions independently associated with a high risk for OSA. This is the first study to demonstrate the prevalence of a high risk for OSA in a nationwide representative sample of the Korean adult population. These findings elucidate the epidemiology and clinical characteristics of those at high risk for OSA.

Insomnia and migraine are closely related; insomnia aggravates migraine symptoms. This study was conducted to investigate the impact of migraine on the clinical presentation of insomnia symptoms. The data of the Korean Headache-Sleep Study (KHSS) were used in the present study. The KHSS is a nation-wide cross-sectional population-based survey regarding headache and sleep in Korean adults aged 19 to 69 years. If a participant’s Insomnia Severity Index (ISI) score ≥ 10, she/he was classified as having insomnia. The clinical presentation of insomnia symptoms was assessed using total and subcomponent scores of the ISI. Of 2695 participants, 290 (10.8%) and 143 (5.3%) individuals were assigned as having insomnia and migraine, respectively. The proportions of migraine (12.8% vs. 4.4%, p < 0.001) and non-migraine headache (59.0% vs. 39.9%, p < 0.001) were higher among individuals with insomnia compared to those without insomnia. Among participants with insomnia, total ISI scores were not significantly different among participants with migraine, non-migraine, and non-headache [median and interquartile range: 13.0 (11.0–17.5) vs. 13.0 (11.0–17.5) vs. 12.0 (11.0–16.0), p = 0.245]. ISI scores for noticeability of sleep problems to others were significantly higher among participants with migraine [3.0 (2.0–4.0) vs. 2.0 (2.0–3.0), p = 0.011] and non-migraine headache [3.0 (2.0–4.0) vs. 2.0 (2.0–3.0), p = 0.001] compared to those without headache history. Other ISI subcomponent scores did not significantly differ between headache status groups. Participants with insomnia had an increased risk of migraine and non-migraine headache compared to those without insomnia. Among participants with insomnia, overall insomnia severity was not significantly influenced by the headache status.

Kim HK, et al. Transl Clin Pharmacol. 2022 Dec;30(4):163-171. https://doi.org/10.12793/tcp.2022.30.e21