Incidence of New-Onset and Worsening Heart Failure Before and After the COVID-19 Epidemic Lockdown in Denmark: A Nationwide Cohort Study

BACKGROUND: The Danish government ordered a public lockdown on March 12, 2020, because of the coronavirus disease 2019 (COVID-19) pandemic We investigated the immediate consequences of such a lockdown for patients with heart failure (HF) METHODS: Using the Danish nationwide administrative databases, we investigated the incidence of new-onset HF and hospitalizations for worsening HF before and after the lockdown (January 1 to March 11 versus March 12 to March 31) in 2020 versus 2019 We also investigated the mortality for all patients with HF and in COVID-19-infected patients with HF RESULTS: Rates of new-onset HF between January 1 and March 11 were comparable for 2020 and 2019 (1 83 versus 1 78 per 10 000 person-years;P=0 19), while hospitalizations for worsening HF were slightly higher in 2020 versus 2019 (1 04 versus 0 93 per 1000 person-years;P=0 02) In the lockdown period, rates of new-onset HF diagnoses (1 26 versus 2 25 per 1000 person-years) and of hospitalizations for worsening HF (0 63 versus 0 99 per 1000 person-years) were significantly lower in 2020 versus 2019 (P for both, l0 0001) Mortality was similar before and after the national lockdown for the population with HF We observed 90 HF patients with diagnosed COVID-19 infection, of whom 37% (95% CI, 23%-50%) died within 15 days CONCLUSIONS: The number of patients hospitalized with worsening HF or diagnosed with new-onset HF was markedly reduced after lockdown but has not yet impacted mortality in HF patients at a population-based level However, these data raise concerns for a potential undertreatment of HF currently that may impact prognosis in the longer term