Many clinicians will remember receiving electronic copies of prepublication versions of these two linked epidemiological studies at the height of the first wave of COVID-19. At the time, they must have been two of the most widely read and debated papers that were available for diabetes clinicians. Facing a potential tidal wave of sick people and not knowing specifically what do to certainly concentrates the mind. The two papers were striking then and remain helpful now.
One is a community-based study and the other reports on deaths in hospital. The methodology is important. We have reasonably robust data about diagnosis of diabetes and the associated risk factors for the population studied. The major difficulty with both papers is that we were much less clear about who had this virus. This has become more obvious as time has passed. The first paper used death certificates for diagnosis of COVID-19. Medical practitioners are required to certify causes of death “to the best of their knowledge and belief”; however, this is without diagnostic proof. Some diagnoses may have included a positive antigen test but not all; we may have been over-diagnosing for some time. Conversely, and perhaps more importantly, a significant number of deaths where COVID-19 was a contributor will have been missed. This is an important source of systematic bias and is acknowledged by the authors.
The second paper is based on hospital deaths related to COVID-19. For the most part (but not completely towards the end of the study period), people were only included if they were antigen-positive on testing. Putting aside the problem of false-negative swabs, this is a more robust cohort and strongly supports the conclusions of the first paper. There is one small figure in the article by Holman et al that is indisputable. This looks at excess deaths for the whole population and for people with diabetes over the time period of the first wave of COVID-19. The numbers are large and much greater than those quoted in the rest of the papers. The implication is that we were significantly underdiagnosing the condition.
Both of the papers tell us that diabetes, whether type 1 or type 2, is a risk factor for death from COVID-19. Ethnicity is also important, as is overweight/obesity. These are messages that we can share with the people we are looking after. On reflection, perhaps the most striking conclusion is the relationship between death and deprivation. The most deprived socioeconomic group had a significantly higher risk of dying from this virus. Before this pandemic there was already a movement to address health inequality. The trends seem to be stronger for people with diabetes than for the general population, which makes is especially important that diabetes specialists play their part in this conversation.
The papers tell us there is a problem but they cannot tell us what to do about it. There is one obvious conclusion that we can draw. Providing good diabetes care in the community, in residential care and in hospital can make a difference to outcomes. Although health systems are disrupted, it is especially important that we focus on raising the standard of diabetes care using the guidance we already have. During this pandemic, we must ensure that standards of diabetes care do not fall, as we know that doing so will improve outcomes for the people we are treating.