At the moment, the epidemic in Italy of COVID-19 continues to spread throughout the entire country. According to data from the Italian Istituto Superiore di Sanità (ISS) infection has continuously grown higher since the latter half of the month of February 2020 (6). As of March 27th, there are still growing cases of infection with a higher trend in men (58%) and 35.8% of those with infection are ≥ 70 years of age.
Of those that have died with COVID-19 (n=7589), 83.7% (n=6351) were ≥ 70 years, while 16.2% (n=1238) were > 69 years (6). Therefore, older age even in Italy would seem to hold an important risk for infection and mortality (7).
It is widely known that Aging is associated with an increased risk for diverse comorbidities. Considering that infection from COVID-19 is strongly associated with severe acute respiratory syndrome (SARS), it would seem obvious that patients with depressed immune response, such as in those patients with Chronic Obstructive Pulmonary Disease (COPD) or Chronic Renal Insufficiency would be at a significantly higher risk for SARS. However, available data from the ISS show that the most common comorbidities observed in all Italians dying with COVID-19 are arterial hypertension (74.7%) and Type 2 Diabetes (30.5%) (6). Interestingly, the same comorbidities have also been found to hold high percentages in Chinese retrospective data from COVID. For example, Yang X et al. (8) found that in 52 non-survivors with COVID-19, 22% had Type 2 Diabetes, while another study found that hypertension was the most common comorbidity reaching 30% in a sample of 191 patients (9). In recently published Chinese report, regarding an in-hospital sample of older persons (n=4,348) with a mean age of 74 years, found that hypertension was the most common comorbidity (63.1% prevalence) and increased to 72.5% in over 80 year olds from Wuhan (10). Indeed, both hypertension and Type 2 Diabetes were associated with a higher odds ratio of in-hospital death with COVID-19 (9). Unfortunately, data regarding regular drug regimens for these comorbidities prior to hospitalization in those dying with COVID in these studies was not assessed. In 2017, a Chinese study underlined that in over a million patients, the most commonly used anti-hypertensive agent was calcium-channel blockers (11).
In addition, patients with COPD had a 5- to 6-fold increase in the ratio of angiotensin receptor-1 (AT-1) to angiotensin receptor-2 (AT-2) in pulmonary regions with marked fibrosis (12). AT-2s have been shown to hold anti-fibrotic properties, while AT-1s seem to hold a role in COPD-lung induced fibrosis (12). Angiotensin converting enzymes 2 (ACE-2) are expressed on myocytes, renal endothelial and epithelial lung cells (13) and have shown to act as receptors for SARS-CoV-2 (14). Thus, one may hypothesize a direct involvement of the virus on cardiac muscle tissue, endothelial and epithelial cells. In addition, it has been suggested that angiotensin 2 type 1 receptor blockers (ARBs) may increase ACE-2 expression and target host response to infection (15). However, ARBs have been shown to improve on endothelial dysfunction by increasing levels of Angiotensin-(1–7), a vasodilator especially present in increased ACE-2 expression (16). At the moment, future studies are needed to identify the pathways related to a potential role of ACE-2 expression on facilitating COVID-19 infection in those undergoing drug treatments with ACE inhibitors and ARBs for hypertension.
At the moment, older patients with diabetes seem to have a significantly higher risk of mortality with COVID-19. Over the years, there has been substantial data underling an important role of the renin-angiotensin system (RAS) on glycemic control (17). In particular, ACE-2 seems to play a role on blocking Angiotensin II- mediated hyperglycemia. ARBs and ACE inhibitors improve glycemia by blocking RAS over activity. It has been recently highlighted that ACE-2 is increased in patients with diabetes undergoing treatment with ACE inhibitors and ARBs (13). The underlying question remains if the increased expression of ACE-2 can protect or increase the risk of the development and mortality associated with COVID-19!
Testing which specific anti-diabetic oral agents are correlated with COVID-19 and mortality in older patients will add novel insight.