Coronavirus is affecting individuals, populations and health systems far beyond infection
Since the emergence of the covid-19 pandemic in Wuhan, it has been noted that, like seasonal flu, older people and those with certain long-term conditions, such as heart disease and chronic obstructive lung disease, are more likely to be admitted to hospital, to need ventilation, and to die from coronavirus (SARS-CoV-2) infection. These are “direct” effects of infection.
However, unlike seasonal flu, the high infectious period and the high transmission rate have made coronavirus particularly deadly in these “at-risk” groups. Unfortunately, it is the treatment and prevention of these same chronic diseases, which are “indirectly” affected by a societal insult that no other virus has inflicted across so many countries in at least a century. Looking at research and practice through a purely infectious diseases focused lens, with a pandemic of this scale, does not emphasise the impact on people with long-term conditions or their care, despite their major direct and indirect burden.
“Excess deaths” has become a key metric to monitor the impact of the pandemic. “Excess” has a double meaning in this context: excess to those deaths expected based on previous official statistics, and excess to those based on the background level of risk, predicted by age, sex and pre-existing conditions. On 17 March, the UK had reported 1950 cases and 81 covid-19 deaths. On 22 March, we published the first model for excess covid-19 deaths on a preprint server. In a large dataset of UK electronic health records from 3.8 million people, we used background risk in individuals to estimate the excess deaths in the population over 1 year. We modelled different population rates of infection and assumed different levels of population impact of the infection. If the infection rate was allowed to reach 10%, we predicted that over 70,000 deaths could occur in England, mainly in the “at-risk” group, which accounts for more than 20% of the population.
As of 12 July, the UK’s covid-19 death toll was 44,830, and most of those deaths have been in people over the age of 70 years and those with pre-existing diseases. Timely policies of social distancing, isolation, testing and tracking could have suppressed the infection rate, thereby protecting the most vulnerable and avoiding excess deaths. In addition, among the 1.7 billion people at most risk globally due to their underlying conditions, treatment of chronic conditions should be prioritised to reduce the risk of severe infection.
Data across countries show excess deaths above and beyond official covid-19 deaths. In the UK, official figures reveal a spike in non-covid deaths during the pandemic. The same has been seen in other countries which have experienced high infection rates, including Italy and the United States. We showed a 60-100% decrease in activity compared with pre-pandemic levels in eight hospitals across China, Italy and England during the pandemic. In China, activity remained below pre-covid-19 levels for two to three months even after easing lockdown, and is still reduced in Italy and England. Similarly, there were dramatic reductions in hospital admissions for chemotherapy (45-66%) and urgent referrals for early cancer diagnosis (70-89%), compared to pre-pandemic levels. The reasons for these decreases are not fully clear, but are at least in part due to patients not attending hospital, due to health system strain, and perhaps also related to lockdown itself.
In England, between 30,000 and 60,000 excess deaths are predicted over the next year in people with cardiovascular diseases (direct effect) if 10% of the population is infected. However, there may be a greater number of indirect deaths (50, 000 to 100,000) due to huge effects on provision of health services. Up to 18,000 people may die due to decreased treatment and prevention of cancers in England. Across countries, under-diagnosis and under-treatment of diseases, ranging from kidney disease and cardiovascular disease to diabetes and cancer, are leading to and will lead to a delayed burden of excess deaths which may not be seen fully for at least a year. It is already entirely plausible that the indirect effects, even before we consider economic and social effects, will outweigh the toll of direct covid-19 deaths, which have been emphasized thus far. Furthermore, lockdown policies may themselves inadvertently lead to increased chronic disease burden, including diabetes and cardiovascular disease, if effects on obesity and physical activity are not mitigated.
What can be done while we wait for vaccines and treatments? Well, the same early, preventive public health measures which have kept covid-19 deaths low in some parts of the world, such as New Zealand or Kerala, have also kept indirect deaths to a minimum. So the first step should have been early lockdown, testing and tracing. Whether in the run up to lockdown, easing of lockdown, or in future waves of the pandemic, it is clear that underlying conditions predict severity and mortality. Therefore, treatment of underlying conditions should be emphasised both to reduce the risk of direct covid-19 deaths and to avoid the unintended consequences of the response to the pandemic, which include deaths due to causes other than covid-19. The second step is to urgently communicate personalised risk to patients, carers, researchers and policymakers. Simple, accessible tools are needed, so that decisions, such as returning to workplaces and seeing family or friends, to staying at home and going on holiday, can be as evidence-based as possible. Only then can the double burden of “direct” and “indirect” deaths, perhaps the most distinguishing feature of this pandemic, be prevented.
Amitava Banerjee is Associate Professor in Clinical Data Science and Honorary Consultant Cardiologist, Institute of Health Informatics, University College London
Competing interests: None declared
Twitter: @amibanerjee1