DISCUSSION

In this Internet-based data intelligence study, we observed that the majority of COVID-19 deaths were elderly (approximately 8 of 10) and males (6 of 10), and most fatalities (3 of 4) occurred in patients with chronic illnesses. The findings were consistent with a recent report in a hospital-based study, ^{Reference Chen, Wu and Chen3} and with the WHO report on COVID-19 in China, ⁴ and demonstrate the usefulness of an Internet-based data intelligence study. Previous studies have not clarified the direct causes of death. Our data indicate that the most common direct cause of death is multiple organ failure (approximately 2 of 3). The initial onset symptoms are not so much saliently worrisome, but the median duration from diagnosis to death was only 9 d, indicating that the disease can worsen rapidly, costing life.

The function of innate immunity and neutrophil function may degrade with aging, exposing the elderly to the more deleterious impact of the new coronavirus infection. Similar to SARS and MERS, COVID-19 presents a clear male sex bias. ^{Reference Channappanavar, Fett and Mack5} Compared with males, the immune response in females may be more vigorous with higher antibody levels following exposure to an infectious agent; ^{Reference Moxley, Posthuma and Carlson6} thus, females may be less vulnerable to the deleterious consequence of COVID-19 infection. It has been speculated that women’s lower susceptibility to viral infections may be related to genetic factors associated with the X chromosome and sex hormones. Another possible explanation for the higher incidence and more male COVID-19 fatalities may be due to that males are likely to spend more time outdoors, increasing the chances of exposure to the virus.

Consistent with previous reports, most (approximately 3 of 4) fatalities occurred in patients with chronic illnesses. ^{Reference Chen, Wu and Chen3,Reference Onder, Rezza and Brusaferro7} The top 4 were hypertension (41.0%), diabetes (29.0%), coronary heart disease (27.0%), and respiratory disorders (23.0%). Previous studies indicate that COVID-19 shares the same receptor with SARS-COV, and the angiotensin-converting enzyme-2 (ACE2) sensitive cell surface receptors mediate the entry of the virus into the target cells. ^{Reference Lu, Zhao and Li8} ACE2, the functional receptor of SARS-COV, is expressed in the islet, through which the virus may invade and destroy the pancreatic islet cells, thus may aggravate diabetes and accelerate the disease progression. The immune system plays a crucial role when the body is confronted with viruses or bacteria. For patients with diabetes, especially those with poor blood glucose control, long-term exposure to hyperglycemia may lead to decreased immune function. Other chronic illnesses may also compromise the patient’s immune defense system leading to severe consequences.

Multiple organ failure, respiratory failure, and circulatory failure were the main direct causes of deaths. Similar to MERS-CoV, ^{Reference Zumla, Hui and Perlman9} multiple organ failure appears to be a common direct cause of death in COVID-19 fatalities. The COVID-19 infection may lead to increased blood capillary permeability of the lungs, ^{Reference Ackermann, Verleden and Kuehnel10} aggravating inflammation and apoptosis, with lung injuries leading to respiratory distress syndrome. The virus may set off an immune inflammatory response storm, causing tissue damages in multiple organs leading to multiple organ failure.

This study has some limitations. First, we did not have the laboratory data in this Internet reports-based study. The reported clinical characteristics are relatively limited in Internet reports. It is unclear whether there is a selection bias in Internet reports of COVID-19 fatalities compared with those fatalities in the general population. However, our data on age and sex distributions of COVID-19 deaths are consistent with the recent report on 113 deaths in a single large hospital-based study in Wuhan, China. ^{Reference Chen, Wu and Chen3}

In conclusion, COVID-19 deaths are mainly elderly and patients with chronic diseases, especially cardiovascular disorders and diabetes. Multiple organ failure is the most common direct cause of death. Our findings may inform clinical health-care professionals in better management of severe COVID-19 patients in fighting the emerging pandemic.