The Dual Burden of Type 1 Diabetes and COVID-19

Abstract

In the year after the first case of coronavirus disease 2019 (COVID-19) was identified in the United States on 21 January 2020, the nation s death toll from the virus has passed 400000, a number on par with U.S. fatalities in World War II (405399) (1). From as early as February 2020, data from China indicated that the COVID-19 case-fatality rate was 3 times higher in patients with diabetes than in those without it (2). As the pandemic spread beyond China, mounting evidence showed that, although individuals with diabetes were no more prone to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection than the overall population, they made up a disproportionately higher percentage of severe COVID-19 cases (3). These early analyses largely did not distinguish between types of diabetes. Yet, because of its higher worldwide prevalence, these data likely largely reflected the experience of patients with type 2 diabetes mellitus (T2DM). This early lack of data on patients with type 1 diabetes mellitus (T1DM) may have influenced the Centers for Disease Control and Prevention s (CDC) current guidance, which states that adult patients with T2DM “are at increased risk” for severe illness from COVID-19, whereas those with T1DM “might be at an increased risk” for severe illness (4). How should physicians extrapolate what we know about SARS-CoV-2 and T2DM to patients with T1DM? Fortunately, by the second half of 2020, data emerged quantifying COVID-19–related morbidity and mortality in patients with T1DM (5–8). These analyses showed that patients with T1DM experienced markedly higher adjusted odds of hospitalization (6), severity of illness (6, 8), and death (5, 8) than patients who did not have T1DM (Table). In conflict with present CDC guidance, these data further demonstrate that, when compared with individuals without diabetes, people with T1DM have similar to slightly higher adjusted risk for adverse COVID-19 outcomes than people with T2DM. Notably, we have found that patients with COVID-19 and well-controlled T1DM have 3-fold higher unadjusted odds for hospitalization than those who do not have diabetes. This evidence indicates that COVID-19 presents an elevated threat to those living with T1DM. In addition to quantifying the excess risk for poor COVID-19 outcomes in T1DM, recent studies shed light on patient subgroups that are particularly vulnerable. For example, a population-wide analysis of 264390 patients with T1DM found that the adjusted hazard ratio for COVID-19–related death for Black versus White patients was 1.77 (95% CI, 1.25 to 2.49) (7). When patients in the most deprived quintile of the deprivation index were compared with those in the least deprived quintile, the adjusted hazard ratio was 1.93 (CI, 1.36 to 2.72). By comparison, when the investigators analyzed the association of mortality and glycemic control, the only statistically significant association was among patients with hemoglobin A1c levels greater than 10.0% compared with those with levels of 6.5% to 7% (adjusted hazard ratio, 2.23 [CI, 1.50 to 3.30]). Collectively, available evidence suggests that even if patients with T1DM could continually optimize glycemia and societal health inequities could be rectified, these individuals would remain at increased risk for poor outcomes from COVID-19 compared with people without diabetes. In December 2020, Pfizer-BioNTech (9) and Moderna (10) reported safety and efficacy data from placebocontrolled randomized clinical trials of their COVID-19 vaccines to the U.S. Food and Drug Administration. The effectiveness of the vaccines in preventing confirmed COVID-19 were 95.0% (CI, 90.3% to 97.6%) and 94.5% (CI, 86.5% to 97.8%), respectively. Moreover, severe COVID-19 occurred only once among vaccinated participants. Of importance, efficacy findings were consistent across nearly every subgroup