Delirium in COVID-19 and post-liver transplant patients: an observational study.

Objective: Delirium is a major complication in hospitalised patients. This study aimed to compare the mortality trends of patients with delirium according to the underlying physical condition.

Methods: Hospitalised patients diagnosed with delirium by the Modena Consultation-Liaison Psychiatry Service (Italy) during 2020 were enrolled. Three groups were identified: COVID; after orthotopic liver transplant (OLT); other conditions. The full medical records were screened to retrieve socio-demographic and clinical data. INTERMED score and Delirium Rating Scale were used to retrospectively rate bio-social-complexity and delirium severity. Early (20 days) and end of study (31^st January 2021) mortality were ascertained for each subject.

Results: A total of 103 patients were enrolled. Patients hospitalised for COVID showed higher INTERMED scores (two-tailed t-test, p = 0.019) and higher 20-day mortality (HR = 3.68, p = 0.014). When considering a 1-year follow-up, the main predictor of mortality was patients' age in all three subgroups (HR = 1.06; p = 0.003).

Conclusion: Our results suggest that patients hospitalised for COVID-19 with delirium showed higher bio-psycho-social complexity and higher short-term mortality, regardless of the severity of delirium. OLT patients showed lower mortality and bio-psycho-social complexity, despite being still considered as 'complex', according to the INTERMED score. Future research should focus on understanding the underlying mechanisms in the relationship between delirium and mortality.Key pointsPatients hospitalised for COVID-19 with delirium were found at risk of higher short-term mortality and higher bio-psycho-social complexity.OLT patients showed lower overall mortality and lower bio-psycho-social complexity than the other two groups, despite being still in the 'complex' range according to the INTERMED score.Future research should assess the areas of impact of delirium in patients affected by COVID-19, considering short- and long-term outcomes.