In a recent study published in Scientific Reports, researchers investigated chronic critical illness (CCI) in coronavirus disease 2019 (COVID-19) survivors who sought intensive care unit (ICU) admission and were on mechanical ventilation due to severe infection by severe acute respiratory syndrome coronavirus -2 (SARS-CoV-2).

Background

Advancements in intensive care have substantially improved the survival rates of patients with acute surgical, neurological, or cardiac critical illnesses. In severe cases, COVID-19 also led to CCI.

CCI often affects older patients with sepsis and underlying comorbid conditions and diminishes their health-related quality of life (HRQoL). Moreover, ICU survivors have impaired physical and psychological health and cognition. 

Consequently, they require highly resource-intensive, long-term critical care, which levies extraordinary healthcare costs on the system, individuals, and their families. Thus, it is crucial to study the long-term outcomes (beyond survival) in COVID-19 ICU survivors even when they received short-term ICU therapy.

About the study

In the present study, researchers recruited a prospective cohort of adult CCI COVID-19 patients admitted to a neurorehabilitation center in Germany to determine their health outcomes and the HRQoL three, six, and 12 months after they sought discharge.

They relied on a consensus-derived American definition to determine the presence of CCI mandating a minimum of eight days of ICU stay and meeting one of any six clinical conditions, ≥96 h of acute mechanical ventilation, sepsis, tracheotomy, stroke, severe wounds, and traumatic brain injury. These patients received ~100 minutes of some neurorehabilitation therapies every day.

The researchers conducted five study visits at different time points, where participants underwent functional tests and furnished information about their living conditions. Additionally, the team extracted data on ICU treatment complications, characteristics, and pre-existing comorbidities from their medical records. 

They also performed electromyography and nerve conduction studies to investigate critical illness myo- and neuropathy. The Fatigue Severity Scale-7 (FSS-7) helped assess fatigue, with a cutoff of ≥4 indicating fatigue. Likewise, a score of >7 on the Hospital Anxiety and Depression Scale (HADS) indicated clinically relevant anxiety and depression.

Furthermore, the EuroQol-5 dimensions-5 level (EQ-5D-5L) measured HRQoL, with a visual analog scale of 0-100, indicating the best health state. The team also assessed frailty, overall disability, and dyspnea using specific scales.

The team used linear mixed-effect models to study the impact of preclinical health conditions and ICU treatment characteristics on HRQoL, fatigue, anxiety, and depression over time. It adjusted for various covariates such as age, gender, comorbidities, etc. The team visually inspected model assumptions and reported the findings.

Results

Of 130 patients enrolled in this study between June 2020 and January 2022, only 97 were included in the final analysis. The average length of stay in the ICU and mechanical ventilation was 52 and 39 days, respectively. 

The prevalence of fatigue, anxiety, and depression was notably high between discharge (visit 2) and three months follow-up and remained high until the last study visit, i.e., one year after discharge from rehabilitation. 

Accordingly, HRQoL remained limited, with no noteworthy improvement until the last study visit. It remained almost unchanged at a substantially lower level compared to the age-matched general population in Germany (index value: 0.63 ± 0.33 vs. 0.87 ± 0.20). However, frailty, overall disability, and dyspnea slightly improved after admission to neurologic rehabilitation. 

Since systemic inflammation primarily drives critical illness polyneuropathy and myopathy and 84% of the cohort was diagnosed with it, 42% and 39% of patients in this study experienced anxiety and depression, respectively, and 68% and 84% reported problems with walking and pain or discomfort, respectively, 12 months after discharge from rehabilitation.

Furthermore, results of the EQ-5D-5L and the HADS showed that the majority of participants suffered from post-intensive care syndrome (PICS) even more than one year after the infection.

Conclusions

Overall, the burden of symptoms was high even one year after discharge in CCI patients who recovered from COVID-19.

55%, 42%, 40%, 77%, and 84% experienced substantial fatigue, anxiety, depression, problems with day-to-day work, and pain and discomfort, respectively.

These patients should receive special medical attention even after discharge, especially for mental health issues.