Can Inflammation Profiling Predict Recovery From Long-COVID?

Susan Kreimer for Medscape

January 05, 2022

The study covered in this summary was published in as a preprint and has not yet been peer-reviewed.

Key Takeaways

  • The sequelae of a hospital admission with COVID-19 remain substantial 1 year after discharge across a range of health domains.

  • Patient-perceived health-related quality of life remains reduced at 1 year compared to prehospital admission.

  • Systemic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

  • In a diverse UK population of adult survivors of COVID-19, the minority of participants felt fully recovered 1 year after hospital discharge with minimal improvement after their 5-month assessment.

  • The most common ongoing symptoms were fatigue, muscle pain, physically slowing down, poor sleep, and breathlessness.

  • The major risk factors for failure to recover at 1 year were female sex, obesity, and receiving invasive mechanical ventilation (IMV) during the acute illness.

  • There were substantial impairments in health-related quality of life at 5 months and 1 year compared to retrospective self-reported preinfection levels.

Why This Matters

  • Both pharmacologic and nonpharmacologic interventions are urgently needed to improve the ongoing significant burden of symptoms, reduced exercise capacity, and large decrements in health-related qualify of life after 1 year.

  • These findings support the use of a precision medicine approach with potential treatable traits of systemic inflammation and obesity.

  • Without effective treatments, long-COVID has the potential to become a highly prevalent new long-term condition.

Study Design

  • The PHOSP-COVID prospective longitudinal cohort study recruited adults hospitalized with COVID-19 across the UK.

  • Researchers assessed recovery using patient-reported outcomes measures, physical performance, and organ function at 5 months and 1 year after hospital discharge.

  • They performed hierarchical logistic regression modeling for patient-perceived recovery at 1 year.

  • Cluster analysis was undertaken using clinical outcomes at 5 months.

  • Inflammatory protein profiling from plasma was conducted at the 5-month visit.

Key Results

  • A total of 2320 participants were assessed 5 months after discharge, and 807 participants completed both 1-month and 1-year visits. Of these, 35.6% were female, mean age 58.7 years, and 27.8% received IMV.

  • The proportion of patients reporting full recovery was unchanged between 5 months (501/1965; 25.5%) and 1 year (232/804; 28.9%).

  • Factors associated with being less likely to report full recovery at 1 year were female sex, obesity, and IMV.

  • Cluster analysis (n = 1636) corroborated the previously reported four clusters: "very severe," "severe," "moderate/cognitive," and "mild" relating to the severity of physical, mental health, and cognitive impairments at 5 months in a larger sample.

  • There was elevation of inflammatory mediators of tissue damage and repair in both the "very severe" and the "moderate/cognitive" clusters compared to the "mild" cluster, including interleukin-6, which was elevated in both comparisons.

  • Overall, there was a substantial deficit in median EQ5D-5L utility index from pre-COVID, with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

  • Overall, 25.5% of patients felt fully recovered at 5 months post discharge, and 28.9% at 1 year.


  • There was selection bias for participants returning for a 1-year visit, although the researchers did not find overt differences between the demographics or 5-month recovery status between attendees and nonattendees of the 1-year visit.

  • Notwithstanding this limitation, even with the assumption of all participants with missing data having fully recovered, then the highest estimate is 60% of participants feeling fully recovered at 1 year demonstrating a substantial proportion with ongoing new morbidity.

  • This cohort has a higher proportion of patients requiring IMV than typically seen in UK hospitals, and therefore the results may not be directly generalizable to the wider population.

  • Data linkage to electronic patient records is in process but is not currently available, so in the current report, preexisting comorbidities were self-reported, and data regarding hospital admissions and mortality in the first year are unavailable.

  • Persistent inflammation may be an underlying ongoing impairment in some participants and requires further investigation and replication.

  • These findings cannot confirm causality but suggest that these associations should be further investigated as part of mechanistic studies and clinical trials.

Study Disclosures

  • The authors report no disclosures.

This is a summary of a preprint research study Clinical characteristics with inflammation profiling of Long-COVID and association with one-year recovery following hospitalisation in the UK: a prospective observational study, by Rachael A. Evans and colleagues from University of Leicester in Leicester, UK provided to you by Medscape. The study covered in this summary was published in as a preprint and has not yet been peer reviewed. The full text of the study can be found on


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