Excess cardiovascular deaths in the beginning of COVID-19 outbreak

Importance

The healthcare demand created by the COVID-19 pandemic was far beyond the hospital surge capacity in many countries, resulting in possible negative influence on prognosis of other severe diseases, such as cardiovascular disease (CVD).

Objective

To assess the impact of the COVID-19 outbreak on CVD-related hospitalizations and mortality.

Design

Community-based prospective cohort study.

Setting the UK Biobank population.

Participants

421,717 UK Biobank participants who were registered in England and alive on December 1 ^st 2019.

Main outcomes and measures

The primary outcome of interest was CVD death, as deaths with CVD as a cause of death according to the death registers. We retrieved information on hospitalizations with CVD as the primary diagnosis based on the UK Biobank hospital inpatient data. The study period was between December 1 ^st 2019 and May 30 ^th 2020, and we used the same calendar period of the three preceding years as the reference period. Standardized mortality/incidence ratios (SMRs/SIRs) with 95% confidence intervals were used to estimate the relative risk of CVD outcomes during the study period, compared with the reference period, to control for seasonal variations and aging of the study population.

Results

We observed a distinct increase in CVD-related deaths in March and April 2020 as compared to the corresponding months of the three preceding years. The observed number of CVD death (n=217) was almost doubled in April, compared with the expected number (n=120), corresponding to an SMR of 1.81 (95% CI 1.58-2.06). We observed a sharp decline of CVD hospitalization in March (n=841) and April (n=454), compared with the expected number (n=1208 for March and 1026 for April), leading to an SIR of 0.70 (95% CI 0.65-0.74) for March and 0.44 (95% CI 0.40-0.48) for April. There was also a clear increase of death, but a clear decrease of hospitalization, in March and April for all the five major subtypes of CVD.

Conclusions

We observed a distinct excess in CVD deaths in the beginning of the COVID-19 outbreak in the UK Biobank population. In addition to CVD complications of SARS-CoV-2 infections, the reduced hospital capacity might have contributed to the observed excess CVD deaths.

Key Points