Prevalence and associations of insomnia after COVID-19 infection.

Study objectives: Sleep disturbances in "long COVID" are common, but the associations between the severity of sleep problems and the severity of COVID infection are unclear. We evaluated the prevalence, persistence, comorbidities, and clinical effects of insomnia following recovery from acute COVID-19 infection in a COVID-specific clinic.

Methods: Inpatients discharged after COVID infection and outpatients referred for persistent post-COVID symptoms were surveyed on insomnia severity (Insomnia Severity Index, ISI), other neuropsychological symptoms, cardiopulmonary symptoms and physiological functions (6 minute walk distance and others), and functional outcome and quality of life (QOL). Multivariable regression models evaluated the severity of ISI against independent variables.

Results: A total of 280 patients met criteria at the initial visit. The prevalence of significant insomnia at the initial visit was 50% and 42% at the subsequent visit (obtained in 78 of the 280 patients). Lower age, female sex, non-white race, and non-Hispanic ethnicity were significantly associated with worse initial ISI scores. More severe symptoms of anxiety and depression were strong correlates with worse ISI scores. Interval improvements in insomnia severity correlated with improvements in anxiety and post-traumatic stress disorder (PTSD) scores. Physiological sequelae of infection did not correlate with insomnia at any stage.

Conclusions: Initial and persistent insomnia is common in long COVID. Treatment for insomnia with the use of evidence based approaches (such as cognitive behavioral therapy for insomnia) may best suit this particular post-COVID symptom.