The results of this study clearly indicate that patients with severe OSA, although well controlled by CPAP treatment, have a poor perceived sleep quality compared to healthy controls that has greatly worsened after the onset of the COVID-19 pandemic. Although high rates of sleep disturbance have been reported across all countries during this dreadful event, it is noteworthy that the prevalence rate of sleep disturbance that we found among patients with OSA (66%) is exceptionally high. In these patients we showed a strict correlation between sleep disturbance and the level of anxiety and depression caused by the pandemic. The prevalence of these symptoms did not differ between OSA and healthy subjects.
To our knowledge this is the first study investigating the effect of the COVID-19 pandemic on perceived sleep quality and psychological stress in patients with obstructive sleep apnea. Anxiety, depressive mood and sleep disturbance have been broadly reported during lockdown periods following the first wave of the COVID-19 pandemic, from March to June 2020 [3, 5, 6]. The emotional distress has been associated with the fear to be infected, forced home confinement and social isolation, economical instability and worries about the future . During this period approximately one third of previously good sleepers complained the occurrence of sleep disturbance across all continents [2, 3].
Italy, where this study was carried out, has been the gateway of the pandemic to Europe in February 2021. For this reason, in this country, one of the highest level of emotional distress in the world has been recorded. Casagrande et al. in an early study showed that, after the COVID-19 outbreak, among 2291 subjects from the general population, 57.1% complained poor sleep quality. A significant relationship was evidenced between sleep quality and generalized anxiety or symptoms of post-traumatic distress . These data were comparable to those reported in China after the outspread in Wuhan in December 2019 .
One first observation is that during lockdown periods home confinement has produced a change in people’s sleep habits as generally the population confined at home delayed bed-time and slept longer than usual . However, it is noteworthy that a longer time spent in bed simply reflects more time spent at home and does not indicate a good quality of sleep, that in fact worsens . In our sample, most of the patients and healthy controls did not change their bed-time and total time spent in bed in the pandemic period. Nevertheless, in line with earlier observations, sleep latency significantly increased in both . It is noteworthy that during the pandemic our patients showed an optimal adherence to CPAP treatment (mean average use > 6 h/night), that, differently from what it has been recently reported in a large cohort study, was not different from the pre-pandemic period .
An altered sleep pattern is an hallmark of untreated OSA and up to 100% of the patients report a subjective sensation of poor sleep quality with a PSQI score well above the cut-off limit . Treatment with CPAP clearly improves sleep architecture, restoring sleep stages and reducing the number of arousals . Though, the subjective sensation of satisfying sleep can be differently affected, perhaps to the discomfort given by the CPAP itself. Our patients, well controlled and adherent to CPAP treatment, had an high score at the PSQI questionnaire referring to the pre-pandemic period, with 54% of the patients reaching the score of a poor sleeper compared to 29% of the controls. This is not surprising, as a previous study on patients treated with CPAP reported a mean PSQI score of 6.6, in good agreement with our mean score of 6.4 . Although during the pandemic the rate of self-reported sleep disturbance increased to a similar extent in patients and in healthy controls, the rate in patients with OSA was exceptionally high. It is conceivable therefore that the increased difficulty in sleeping and the COVID-19-related emotional distress may further contribute to worsen health quality and quality of life in these patients.
This is the first study addressing sleep issues during the pandemic in OSA, however few previous studies have been carried out in patients affected by other chronic conditions [26,27,28]. One large study in UK showed that, during the pandemic, older people with physical disabilities had more symptoms of depression and anxiety compared to people without a physical disability. Self-reported poor sleep quality was evidenced in 49.9% of people with disability and in 39.5% of people without . These differences were accompanied by lower levels of social contact in people with disability, while patients with OSA, in most of the cases live with their family, regularly work and have a normal social life.
Another recent study evaluated the impact of the COVID-19 pandemic on patients with at least one chronic non-communicable disease including hypertension, diabetes, cardiovascular or respiratory disease. Compared to healthy controls, people with such chronic conditions had a 36% greater chance of impaired sleep, strictly associated with a state of emotional stress . The high level of psychological distress in patients with chronic diseases has been explained by the anxiety arising from the fear of contagion, as this event may be particularly dangerous in this fragile population . It is now acquired that patients with OSA are at high risk of developing severe COVID-19 . Our data indicate that although a number of patients complained symptoms of anxiety and depression, still the proportion was similar to the control group, indicating that the emotional distress in these patients is not divergent from the general population. Indeed the rate of self-reported sleep disturbance that we have found in patients with OSA is the highest, compared to previous data reported in the literature in the general population and in other chronic conditions . This high prevalence is explained by the fact that in basal condition the perceived quality of sleep in these patients is poor and in the pandemic period it is worsened by worries that affect also healthy subjects. In fact, we found a strict correlation between the PSQI and the PHQ-9 and, to a lesser extent, the CAS score. Thus, symptoms of depression are a strong determinants of poor sleep quality. Depression is common in patients with OSA, although, to avoid confusion, we excluded from the study those who reported psychological symptoms before initiating CPAP. Of course we cannot completely exclude the presence of previous depression/anxiety, however this is unlikely as our patients scored similarly to healthy subjects. Sleep disturbance reduces daytime functioning further worsening the general state of anxiety/depression, so that a vicious circle, difficult to break, is generated. A remarkable study has shown that the level of anxiety about COVID-19 positively correlated with insomnia severity and suicidal ideation . Clearly, the high prevalence of sleep disturbance may be devastating in fragile individuals as patients with OSA are. On limitation of this study is that we used a PSQI questionnaire not only to assess current sleep quality, but also to collect data referring to the a previous period, before the on-set of the pandemic, so we assumed that some details could be omitted or forgotten. Although this use of the PSQI is unusual, we felt that patients were quite confident when recalling their sleep habits before the pandemic. In addition, the same approach was used for controls and data obtained in our controls were perfectly in line with previous published data.
In conclusion, our data indicate that in patients with severe OSA treated with CPAP the quality of sleep, already poor before the pandemic, dramatically worsened after the onset of the COVID-19 pandemic. The prevalence rate of perceived sleep disturbance that we found in OSA is the highest reported in the literature, among healthy individuals or patients affected by other chronic diseases. During the first wave of the pandemic the level of emotional stress in patients with OSA did not differ from healthy subjects and was strictly associated with the occurrence of sleep disturbance. A further deterioration of sleep quality is a fearsome event in the life of patients who face life-long sleep problems, therefore great attention must be paid to their mental health.