People with Long COVID after hospitalisation face limited recovery after one year

People who were hospitalised with COVID-19 and continued to experience symptoms at five months show limited further recovery one year after hospital discharge, according to the latest results of the PHOSP (Post-Hospitalisation) COVID study, released as a pre-print on medRxiv.

The study also confirmed earlier research that people who were less likely to make a full recovery from COVID-19 were female, obese, and required invasive mechanical ventilation (IMV) to support their breathing during their hospital stay.

UCLH and UCL were one of the largest recruiters to the PHOSP-Covid study. The UCLH and UCL portion of the study is led by Co-Principal Investigators Dr Michael Marks and Prof Jeremy Brown, with work supported by the National Institute for Health Research (NIHR) UCLH BRC. The study is led overall by the University of Leicester.

Researchers from 83 hospitals across the UK assessed 2,230 adults who had been hospitalised with COVID-19. All participants completed a five-month assessment. So far, 807 people have completed both the five-month and 12-month assessments. Recovery was measured using patient-reported data, physical performance and organ function tests. Participant blood samples at the five-month visit were analysed for around 300 substances linked to inflammation and immunity.

They found that one year after hospital discharge, less than 3 in 10 patients on the study reported they felt fully recovered, largely unchanged from 2.5 in 10 at five months. The most common ongoing symptoms were fatigue, muscle pain, physically slowing down, poor sleep and breathlessness.

Participants felt their health-related quality of life remained substantially worse one year after hospital discharge, compared to pre-COVID. This suggests the physical and mental health impairments reported in the study are unlikely to be pre-existing conditions.

A cluster analysis, which is a mathematical method to group participants according to similar traits and characteristics, identified four distinct groups based on the severity of physical, mental and cognitive impairments experienced at five months. The number of persistent symptoms was much higher in the ‘very severe’ group compared to the ‘mild’ group. In all clusters, there was little improvement in physical and mental health from the five-month to one-year assessments.

The researchers compared the blood profiles across the four clusters. They identified higher levels of substances associated with whole-body inflammation and molecules associated with tissue damage and repair, in participants with very severe-Long COVID compared to mild. They also found a pattern of substances linked to poor cognition (‘brain fog’) in the cluster of patients reporting symptoms such as ‘brain fog’ or slowed thinking, suggesting possible neuro-inflammation. 

The PHOSP-COVID study is available as a pre-print, which means it is yet to be checked by other scientists.