This article provides an overview of the clinical evidence on the poorer clinical outcomes of COVID-19 infection in patients with diabetes versus patients without diabetes, including in specific patient populations, such as children, pregnant women, and racial and ethnic minorities.

COVID-19 and Diabetes: A Collision and Collusion of Two Diseases — Diabetes 2020 Oct; dbi200032. https://doi.org/10.2337/dbi20-0032

In the article above the researchers reviewed nearly 90 studies.

Type 2 diabetes (T2D) is defined by a single metabolite, glucose, but is increasingly recognized as a highly heterogeneous disease, including individuals with varying clinical characteristics, disease progression, drug response, and risk of complications. Identification of subtypes with differing risk profiles and disease etiologies at diagnosis could open up avenues for personalized medicine and allow clinical resources to be focused to the patients who would be most likely to develop diabetic complications, thereby both improving patient health and reducing costs for the health sector. More homogeneous populations also offer increased power in experimental, genetic, and clinical studies. Clinical parameters are easily available and reflect relevant disease pathways, including the effects of both genetic and environmental exposures. We used six clinical parameters (GAD autoantibodies, age at diabetes onset, HbA_1c, BMI, and measures of insulin resistance and insulin secretion) to cluster adult-onset diabetes patients into five subtypes. These subtypes have been robustly reproduced in several populations and associated with different risks of complications, comorbidities, genetics, and response to treatment. Importantly, the group with severe insulin-deficient diabetes (SIDD) had increased risk of retinopathy and neuropathy, whereas the severe insulin-resistant diabetes (SIRD) group had the highest risk for diabetic kidney disease (DKD) and fatty liver, emphasizing the importance of insulin resistance for DKD and hepatosteatosis in T2D. In conclusion, we believe that subclassification using these highly relevant parameters could provide a framework for personalized medicine in diabetes.

Subtypes of Type 2 Diabetes Determined From Clinical Parameters — Diabetes 2020 Oct; 69(10): 2086-2093. https://doi.org/10.2337/dbi20-0001

Not just potential for personalized medicine in the treatment of diabetes but perhaps a framework for better risk stratification and selection in life insurance.

Intakes of Folate, Vitamin B₆, and Vitamin B₁₂ in Relation to Diabetes Incidence Among American Young Adults: A 30-Year Follow-up Study

RESULTS During 30 years (mean 20.5 ± 8.9) of follow-up, 655 incident cases of diabetes occurred. Intake of folate, but not vitamin B₆ or vitamin B₁₂, was inversely associated with diabetes incidence after adjustment for potential confounders. Compared with the lowest quintile of total folate intake, the multivariable-adjusted hazard ratios (95% CI) in quintiles 2–5 were 0.85 (0.67–1.08), 0.78 (0.60–1.02), 0.82 (0.62–1.09), and 0.70 (0.51–0.97; P_trend = 0.02). Higher folate intake was also associated with lower plasma homocysteine (P_trend < 0.01) and insulin (P_trend < 0.01). Among supplement users, folate intake was inversely associated with serum C-reactive protein levels (P_trend < 0.01).

CONCLUSIONS Intake of folate in young adulthood was inversely associated with diabetes incidence in midlife among Americans. The observed association may be partially explained by mechanisms related to homocysteine level, insulin sensitivity, and systemic inflammation.

Intakes of Folate, Vitamin B₆, and Vitamin B₁₂ in Relation to Diabetes Incidence Among American Young Adults: A 30-Year Follow-up Study — Diabetes Care 2020 Oct; 43(10): 2426-2434. https://doi.org/10.2337/dc20-0828

Folate is a B vitamin that occurs naturally in foods such as green leafy vegetables, citrus fruit, and beans. So eat your greens and beans. Taking a supplement can’t hurt either. My multivitamin has plenty of folate.