Increased frequency and mortality in persons with neurological disorders during COVID-19.

Determining the frequency and outcomes of neurological disorders associated with COVID-19 is imperative for understanding risks as well as recognition of emerging neurological disorders. We investigated the susceptibility and impact of SARS-CoV-2 infection among persons with premorbid neurological disorder rs, as well as the post-infection incidence of neurological sequelae in a case-control population-based cohort. Using health service data collected from March 1, 2020, to June 30, 2021, we constructed a cohort of SARS-CoV-2 RNA-positive (n=177,892) and -negative (n=177,800) adults who were age-, sex-, and comorbidity-matched and underwent RT- PCR testing at similar times. COVID-19 associated mortality rates were examined within the cohort. Neurological sequelae were analysed during the acute (less than three months) and the post-acute (three to nine months) phases post-infection. The risk of death was significantly greater in the SARS-CoV-2 RNA-positive (2,140 per 100,000 person years) compared to RNA-negative (922 per 100,000 person years) over a follow-up of 9 months, particularly amongst those with premorbid neurological disorders: adjusted odds ratios (aOR, 95% CI) in persons with a prior history of parkinsonism (1·65, 1·15-2·37), dementia (1·30, 1·11-1·52), seizures (1·91, 1·26-2·87), encephalopathy (1·82, 1·02-3·23), and stroke (1·74, 1·05-2·86). There was also a significantly increased risk for diagnosis of new neurological sequelae during the acute time phase after COVID-19 including encephalopathy (2·0, 1·10-3·64), dementia (1·36, 1·07-1·73), seizure (1·77, 1·22-2·56), and brain fog (1·96, 1·20-3·20). These risks persisted into the post-acute phase after COVID-19 during which inflammatory myopathy (2·57, 1·07-6·15) and coma (1·87, 1·22-2·87) also became significantly increased. Thus, persons with SARS-CoV-2 infection and premorbid neurological disorders are at greater risk of death while SARS-CoV-2 infection was complicated by increased risk of new onset neurological disorders in both the acute and post-acute phases of COVID-19.