Outcomes
Diabetes was a common comorbidity in COVID-19 patients who were either admitted to ICU or died. 20-22 In a meta-analysis that included 1382 patients hospitalised for COVID-19, diabetes was identified as a risk factor for both ICU admission (OR 2.79, 95 % CI 1.85 to 4.22, p < 0.0001) and mortality (3.21, 1.82 to 5.64, p < 0.0001). 23 In another meta-analysis of 1936 COVID-19 patients, diabetes significantly correlated with COVID-19 severity (OR 2.67, 95% CI 1.91 to 3.74, P<0.01).24 Prevalence of diabetes was also double in patients with COVID-19 who required ICU admission compared to those who did not.25 Diabetes was the second most common morbidity in patients who reached a composite outcome of mechanical ventilation or death (26.9%) only second to hypertension (35.8%).26 An outcome study has shown that in patients with COVID-19 who developed acute respiratory distress syndrome (ARDS), more patients had diabetes (19.0%) compared with those who did not (5.1%), respectively (difference, 13.9%, 95% CI 3.6% to 24.2%).27 It has also been reported that diabetes was the most common morbidity (22% in one study and 60% in another) of patients who died in hospital. 28, 29 Compared with patients with non-severe COVID-19, diabetes was more common in severe cases although it did not reach statistical significance (OR 2.07, 95% CI 0.89 to 4.82). 30 In a US retrospective chart review of all patients enrolled in a follow up telemedicine outpatient clinic, the rate of hospitalisation for patients with diabetes was double (10.2%) the rate of hospitalisation for all other patients (5.1%) suggesting that the risk of severe COVID-19 is increased in individuals with diabetes. 31 Retrospective Chinese report has shown that compared with non-diabetes subjects, patients with diabetes were more likely to develop severe COVID-19 disease (P=0.028) with more complications including acute respiratory distress (38.1% vs 19.5%, P=0.001), acute cardiac injury (14.5% vs 5.1%, P=0.016) and non-invasive and invasive mechanical ventilation (P=0.037).32 Diabetes as well as fasting blood glucose were independent risk factors for COVID-19 mortality (HR 3.641, 95% CI 1.086 to 12.214, P=0.036 and 1.187, 1.078 to 1.306, P<0.001, respectively) after adjustment for age, cardiovascular disease, chronic kidney disease and laboratory markers. 32 The recently reported British database analysis of 17,425,445 NHS registered adults showed that 5,683 deaths were attributed to COVID-19 and uncontrolled diabetes (HbA1c >=7.5%) was independent risk factor for mortality (HR 2.36, 95% CI 2.18 to 2.56). 33 Main studies reporting outcomes of patients with diabetes and COVID-19 are summarised in Table 3.