As the COVID-19 pandemic continues to spread, and research related to potential risk factors for COVID-19 mortality continues, it is becoming clear that individuals with underlying comorbidities have a greater risk of death from COVID-19. The exact contribution of different comorbidities is unclear, however. Now, a new study published in the journal PLOS ONE dissects this topic and may help to quantify the risk posed by specific conditions and offer help with the prognosis.
Study: Association of cardiovascular disease and 10 other pre-existing comorbidities with COVID-19 mortality: A systematic review and meta-analysis. Image Credit: SvetaZi / Shutterstock
Earlier Studies Yield Contradictory Results
With many different studies coming up, the contradictions multiply. While some say chronic disease increases the risk of COVID-19 and its severity, others disagree. The differences may arise because of the small number of studies, the variety of methods used, and the sources of bias. There is no doubt that the locales with the highest mortality rates are those regions with the highest prevalence of chronic illnesses.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters and infects human host cells using angiotensin-converting enzyme 2 (ACE2), an enzyme and receptor found in many tissues, such as the heart, kidney, and type II pneumocytes. Some researchers suggest that the use of angiotensin II type 1 receptor blockers (ARBs) may enhance the expression of ACE2 on the cell membranes and thus render the individual more susceptible to the infection and at a higher risk of developing progressive and severe disease. This would include people with hypertension and chronic cardiac failure who are being treated with ARBs.
Most studies carried out in this area so far have covered only certain countries, some of the research, and specific conditions. The presence of significant bias from various sources prevents their conclusions from gaining complete