Study identifies factors predisposing to post-COVID-19 condition (long COVID)

By Melanie Hinze

Research published in JAMA Internal Medicine has found a range of demographic characteristics and comorbidities that place people at a higher risk of developing post-COVID-19 condition (PCC), while also finding that having at least two COVID-19 vaccinations reduces the risk of developing long-term complications of COVID-19.

The UK researchers conducted a systematic review and meta-analysis of 41 studies, including 860,783 patients aged 18 years and over, where they had searched for terms including ‘long-COVID-19’, ‘post-COVID-19’ and ‘chronic COVID-19’ in studies published up to December 2022.

They found that women had a 1.56 times increased risk of developing persistent symptoms of three months or more after the acute phase of COVID-19. People aged over 40 years had a 1.21 times increased risk of developing PCC, compared with those aged 18 to 40 years. Those with a BMI of 30kg/m2 or higher were 1.15 times more likely to develop PCC and smokers were 1.10 times more likely.

Patients with comorbidities including anxiety and/or depression, asthma, COPD, diabetes, ischaemic heart disease and immunosuppression had a significantly increased risk of developing PCC. People who needed hospitalisation or ICU admission during the acute phase of COVID-19 were more than twice as likely to develop PCC as those who were not admitted to hospital or ICU.

Conversely, those who had been vaccinated against COVID-19 with at least two vaccinations had roughly half the risk of developing the persistent symptoms of PCC when compared with those who were not vaccinated.

The researchers said their findings confirmed that PCC was a multifactorial and complex clinical syndrome.

Professor Christine McDonald, Director of the Department of Respiratory and Sleep Medicine at Austin Health, Melbourne, and Professorial Fellow at The University of Melbourne, said ‘the study confirms the importance of vaccination to protect against long COVID,’ noting that this was despite the caveats associated with meta-analyses of observational studies, including some with only small numbers and a high degree of heterogeneity.

Professor McDonald told Medicine Today that the other predisposing factors for PCC, including severity of disease and underlying comorbidities, were consistent with previous reports.

‘It will be interesting to follow the early literature on the roles of nirmatrelvir/ritonavir (Paxlovid) and metformin (the latter study not yet peer reviewed) in preventing long-COVID development,’ she added.

JAMA Intern Med 2023; doi:10.1001/jamainternmed.2023.0750.