he epidemiology and clinical characterization of patients with coronavirus disease 2019 (COVID-19) has been reported. [1][2][3] As angiotensin-converting enzyme (ACE) 2 serves as the receptor for severe acute respiratory syndrome coronavirus 2 to gain entry into cells, 4 ACE2-expressing cells are susceptible to COVID-19 infection. 5 The use of ACE inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) is common treatment in cardiovascular disorders, including hypertension, and data regarding the association of these drugs with ACE2 levels are conflicting. 6,7 However, to our knowledge, there are no clinical data indicating whether patients with hypertension who are taking ACEIs/ARBs have increased severity of illness or risk of mortality during COVID-19 infection and whether these patients should continue to use ACEIs/ARBs or switch to other antihypertensive drugs. MethodsPatients with COVID-19 admitted to the Central Hospital of Wuhan (Hubei Province, China) from January 15, 2020, to March 15, 2020, were included in this retrospective analysis. The study was approved by the institutional ethics board of the Central Hospital of Wuhan and the requirement for informed consent was IMPORTANCE Data are lacking whether patients with hypertension who are taking angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) have increased severity or risk of mortality during hospitalization for coronavirus disease 2019 .OBJECTIVE To investigate the association between ACEIs/ARBs and severity of illness and mortality in patients with hypertension hospitalized for COVID-19 infection.

Melatonin (N-acetyl-5-methoxytryptamine), an indoleamine produced in many organs including the pineal gland, was initially characterized as a hormone primarily involved in circadian regulation of physiological and neuroendocrine function. Subsequent studies found that melatonin and its metabolic derivatives possess strong free radical scavenging properties. These metabolites are potent antioxidants against both ROS (reactive oxygen species) and RNS (reactive nitrogen species). The mechanisms by which melatonin and its metabolites protect against free radicals and oxidative stress include direct scavenging of radicals and radical products, induction of the expression of antioxidant enzymes, reduction of the activation of pro-oxidant enzymes, and maintenance of mitochondrial homeostasis. In both in vitro and in vivo studies, melatonin has been shown to reduce oxidative damage to lipids, proteins and DNA under a very wide set of conditions where toxic derivatives of oxygen are known to be produced. Although the vast majority of studies proved the antioxidant capacity of melatonin and its derivatives, a few studies using cultured cells found that melatonin promoted the generation of ROS at pharmacological concentrations (lM to mM range) in several tumor and nontumor cells; thus, melatonin functioned as a conditional pro-oxidant. Mechanistically, melatonin may stimulate ROS production through its interaction with calmodulin. Also, melatonin may interact with mitochondrial complex III or mitochondrial transition pore to promote ROS production. Whether melatonin functions as a pro-oxidant under in vivo conditions is not well documented; thus, whether the reported in vitro pro-oxidant actions come into play in live organisms remains to be established.

The present study included 658 hospitalized patients with confirmed COVID‐19. Forty‐two (6.4%) out of 658 patients presented with ketosis on admission with no obvious fever or diarrhoea. They had a median (interquartile range [IQR]) age of 47.0 (38.0–70.3) years, and 16 (38.1%) were men. Patients with ketosis were younger (median age 47.0 vs. 58.0 years; P = 0.003) and had a greater prevalence of fatigue (31.0% vs. 10.6%; P < 0.001), diabetes (35.7% vs. 18.5%; P = 0.007) and digestive disorders (31.0% vs. 12.0%; P < 0.001). They had a longer median (IQR) length of hospital stay (19.0 [12.8–33.3] vs. 16.0 [10.0–24.0] days; P < 0.001) and a higher mortality rate (21.4% vs. 8.9%; P = 0.017). Three (20.0%) out of the 15 patients with diabetic ketosis developed acidosis, five patients (26.7%) with diabetic ketosis died, and one of these (25.0%) presented with acidosis. Two (7.4%) and four (14.3%) of the 27 non‐diabetic ketotic patients developed severe acidosis and died, respectively, and one (25.0%) of these presented with acidosis. This suggests that COVID‐19 infection caused ketosis or ketoacidosis, and induced diabetic ketoacidosis for those with diabetes. Ketosis increased the length of hospital stay and mortality. Meanwhile, diabetes increased the length of hospital stay for patients with ketosis but had no effect on their mortality.