Incidence and persistence of post-COVID-19 condition in adults– a matched cohort study in Germany

INTRODUCTION: It is still unknown what proportion of persons suffer from long-term consequences of COVID-19. In October 2021, the World Health Organization (WHO) proposed a definition of post COVID-19 condition (PCC) as symptoms that last at least 3 month after onset of SARS-CoV-2 infection and frequently include fatigue, respiratory symptoms and cognitive dysfunction. METHODS: The WHO definition of PCC was translated into ICD-10-GM Codes and investigated in a cohort of patients with laboratory-confirmed COVID-19 during 2020 and matched to controls in German routine healthcare data. Incidence rates were calculated and incidence rate ratios (IRRs) were estimated for developing any of the predefined diagnoses conditional on a preceding diagnosis of COVID-19. Within the COVID-19 cohort the persistence of PCC was followed up to one year after infection. RESULTS: A cohort of COVID-19 patients in the year 2020 was followed up to 2021-09-30 in routine healthcare data. The incidence in the COVID-19 group compared to matched controls for any investigated symptoms and conditions after three months was accessed. Main contributions were dyspnea (R06.0) and malaise/fatigue (R53). The highest IRR was observed for chronic fatigue syndrome (CFS; G93.3) the lowest for cognitive impairment (F06.7, U51). After one year a minority of the patients still had at least one specific diagnosis. The longest persistence of the symptoms was observed for CFS, cognitive impairment (F06.7, U51) and memory loss/disorientation (R41). CONCLUSIONS: The more specific and serious diagnoses had a higher likelihood to occur in the COVID group compared to the matched control group and also these diagnoses persisted longer in the COVID group compared to less serious diagnoses. Due to the high number of infected people during the first two waves of the pandemic this result translates into considerable burden for the medical system. KEY MESSAGES: • In routine healthcare data of adults more serious ICD-10 diagnoses had a higher likelihood to occur in the COVID-19 cohort compared to the matched control cohort. • Within the COVID-19 cohort more serious ICD-10 diagnoses persisted longer than less serious diagnoses.