Aim of the study:
Rapid emergence and transmission of SARS-CoV-2 significantly impacted mental health. Restrictions, lockdowns and quarantines issued during the wait for vaccines resulted in additional psychological distress in most populations. We aim to describe the impact of perceived stress related to the pandemic and sociodemographic determinants on sleep disturbances in the population of patients with chronic medical conditions, such as psoriasis, kidney transplant recipients and undergoing dialysis.

Subject or material and methods:
During the cross-sectional survey conducted between May and October 2020, we enrolled 270 patients with three different chronic medical conditions. Study sample was examined regarding the reported sleep complaints (Insomnia Severity Index), occurrence of psychopathological symptoms (General Health Questionnaire 28) and their perceived levels of stress related to pandemic (Perceived Stress Scale).

Results:
We observed 25,2% prevalence of ISI scores indicative of clinical insomnia in the group of chronically-ill patients during the first phase of the pandemic. ISI scores were found to be strongly correlated with GHQ28 and moderately correlated with PSS-10 scores. The profiles of reported complaints varied significantly between groups.

Discussion:
There are varied outcomes related to sleep disturbances measured with ISI in the general population depending on the country and phase of pandemic with most of them ranging from 11.5 to 20% .

Conclusions:
Findings of our study suggest that population of patients with chronic conditions, with special emphasis on those who have a simultaneous history of psychiatric or psychological treatment, requires additional attention in order to objectivize and maintain sleep disorders during occurrence of severe stress conditions such as the COVID-19 pandemic.