Background: Long-term outcomes after critical COVID-19 have not been sufficiently studied. This study aimed to describe changes in functional outcome and health-related quality of life (HRQoL) assessed at 3 and 12 months in a cohort of critically ill COVID-19 survivors. A secondary aim was to investigate factors associated with good functional outcome and HRQoL at 12 months. Methods: This prospective multicentre cohort study included critically ill COVID-19 patients admitted to six intensive care units in Sweden between May 2020 and May 2021. Surviving patients were invited to face-to-face follow-ups at 3 and 12 months. A good functional outcome was a Glasgow outcome scale extended ≥7. HRQoL was assessed by the physical and mental component summary of the SF-36v2 Results: Good functional outcome was found in 93/264 (35%) and 138/217 (64%) of survivors at 3 and 12 months, respectively. There was a significant improvement in the SF-36v2 Conclusion: Between 3 and 12 months, functional outcome and physical aspects of HRQoL significantly improved, indicating continued recovery up to at least one year after critical COVID-19. Younger age, low frailty, less comorbidity, and shorter duration of mechanical ventilation were associated with better long-term outcomes. Study registration: ClinicalTrials.gov Identifier: NCT04974775, registered April 28, 2020. Key words: COVID-19, HRQoL, Post intensive care syndrome, intensive care, Post-acute COVID-19 syndrome

The authors have declared no competing interest.

AF and HF were supported by governmental funding of clinical research within the Swedish National Health Service (ALF), regional funding from Region Sk ̊ane, the Swedish Heart-Lung Foundation and Sk ̊ane University Hospital Funds

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Swedish Ethical Review Authority approved the SweCrit COVID-19 study (Dnr: 2020-01955, 2020-03483, 2021-00655)

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

The datasets used and analysed during the current study are available from the corresponding author upon reasonable request