Amid the worldwide outbreak of the COVID-19 pandemic, there have been concerns among people that COVID-19 survivors might be at an increased risk of neurological and psychiatric disorders after some evidence emerged showing that COVID-19 survivors are indeed at increased risk of mood and anxiety disorders in the 3 months after infection.
The Lancet Psychiatry has published a retrospective cohort study and time-to-event analysis, aimed to provide robust estimates of incidence rates and relative risks of neurological and psychiatric diagnoses in patients in the 6 months following a COVID-19 diagnosis. The study used data obtained from the TriNetX electronic health records network, which is a federated network recording anonymised data from electronic health records in 62 healthcare organisations, primarily in the USA, comprising 81 million patients.
The study found that among the 236,379 patients diagnosed with COVID-19, the estimated incidence of a neurological or psychiatric diagnosis in the following 6 months was 33·62% (95% CI 33·17–34·07), with 12·84% (12·36–13·33) receiving their first such diagnosis. For patients who had been admitted to an ITU, the estimated incidence of a diagnosis was 46·42% (44·78–48·09) and for a first diagnosis was 25·79% (23·50–28·25). Regarding individual diagnoses of the study outcomes, the whole COVID-19 cohort had estimated incidences of 0·56% (0·50–0·63) for intracranial haemorrhage, 2·10% (1·97–2·23) for ischaemic stroke, 0·11% (0·08–0·14) for parkinsonism, 0·67% (0·59–0·75) for dementia, 17·39% (17·04–17·74) for anxiety disorder, and 1·40% (1·30–1·51) for psychotic disorder, among others. In the group with ITU admission, estimated incidences were 2·66% (2·24–3·16) for intracranial haemorrhage, 6·92% (6·17–7·76) for ischaemic stroke, 0·26% (0·15–0·45) for parkinsonism, 1·74% (1·31–2·30) for dementia, 19·15% (17·90–20·48) for anxiety disorder, and 2·77% (2·31–3·33) for psychotic disorder. Most diagnostic categories were more common in patients who had COVID-19 than in those who had influenza (hazard ratio [HR] 1·44, 95% CI 1·40–1·47, for any diagnosis; 1·78, 1·68–1·89, for any first diagnosis) and those who had other respiratory tract infections (1·16, 1·14–1·17, for any diagnosis; 1·32, 1·27–1·36, for any first diagnosis). As with incidences, HRs were higher in patients who had more severe COVID-19 (eg, those admitted to ITU compared with those who were not: 1·58, 1·50–1·67, for any diagnosis; 2·87, 2·45–3·35, for any first diagnosis).
The study also found that compared to people that had an influenza infection, infection with Covid-19 has a 62% higher risk of stroke caused by blood clots (ischaemic), and a 71% higher risk of stroke caused by a bleed in the brain (intracranial haemorrhage).
“Our results indicate that brain diseases and psychiatric disorders are more common after Covid-19 than after flu or other respiratory infections, even when patients are matched for other risk factors. We now need to see what happens beyond six months. The study cannot reveal the mechanisms involved, but does point to the need for urgent research to identify these, with a view to preventing or treating them,” said Max Taquet, a co-author of the study, from the University of Oxford.