Endocrine and metabolic aspects of the COVID-19 pandemic

Abstract

COVID-19 infection has tremendously impacted our daily clinical practice as well as our social living organization. Virtually all organs and biological systems suffer from this new coronavirus infection, either because the virus targets directly specific tissues or because of indirect effects. Endocrine diseases are not an exception and some of endocrine organs are at risk of direct or indirect lesion by COVID-19. Although there is still no evidence of higher predisposition to contract the infection in patients with diabetes and/or obesity, the coexistence of these conditions contributes to a worse prognosis because both conditions confer an impaired immunologic system. Cytokines storm can be amplified by these two latter conditions thereby leading to multisystemic failure and death. Glycaemic control has been demonstrated to be crucial to avoiding long hospital stays, ICU requirement and also prevention of excessive mortality. Endocrine treatment modifications as a consequence of COVID-19 infection are required in a proactive manner, in order to avoid decompensation and eventual hospital admission. This is the case of diabetes and adrenal insufficiency in which prompt increase of insulin dosage and substitutive adrenal steroids through adoption of the sick day's rules should be warranted, as well as easy contact with the health care provider through telematic different modalities. New possible endocrinological targets of COVID-19 have been recently described and warrant a full study in the next future.

Keywords: Calcium; Covid-19; Diabetes mellitus; Hypoadrenalism; Malnourishment; Obesity; Pituitary; Thyroid; Vitamin D.

Fig. 1

Different endocrine glands/organs that can be affected by COVID-19: 1) Pituitary: possible hypothalamic-pituitary disfunction and alterations in antidiuretic hormone metabolism. 2) Thyroid: sick euthyroid syndrome; 3) Adrenal: probable higher susceptibility to COVID-19 in adrenal insufficiency and Cushing’s syndrome; 4) Bone. Low vitamin D may be linked to more severe disease Increased risk of hypocalcemia. 5) Testicle: Higher susceptibility and worse outcomes have been reported in men; 6) Diabetes. Worse outcomes in diabetic patients; 7) Obesity. Worse prognosis in obese patients

Fig. 2

Prevalence of diabetes mellitus in hospitalized COVID 19+ versus general population in different countries The prevalence of diabetes is higher in hospitalized patients in USA and Spain, but not in China or Italy

Fig. 3

Possible endocrine and metabolic targets that have been considered for COVID-19 therapy. Different hormones and drugs have been included as possible targets for COVI-19 including melatonin, oxytocin, DPP-4 (human dipeptidyl peptidase 4), ACE-2 (angiotensin converting enzyme-2), estrogens and statins

Fig. 4

Potential mechanisms that link obesity to worse outcomes in COVID-19. Obese patients have 1) a impaired respiratory function; 2) associated cardiovascular, metabolic and thrombotic comorbidities which reduce the capability to cope with COVID-19. In addition, obese patients have 3) increased viral shedding and viral load and 4) an amplified immune response due to altered balance between inflammatory and regulatory cells. During COVID-19 infection there is also an altered immune response that is amplified by the dysregulated immune system of the obese patients