COVID 19 A Prospective Case Control Pathophysiological Study of Long Term Implications

Coronavirus disease 2019 (COVID 19) is primarily a respiratory viral infection. At the time of writing this protocol, more than 25 million people have been affected globally. Of these, more than 850000 have died directly due to the disease. In the Kingdom of Saudi Arabia, there are as of now over 30000 cases and deaths from COVID 19. This has been declared as a Pandemic by WHO and has brought normal life to a standstill. There are many uncertainties regarding the pathophysiology and clinical course of this disease. It is estimated that 80 percent of those infected will not need special care. However, 1 in 5 (20%) patients will require hospitalization. Of these, typically, 5 percent will be critically ill and ventilated. Of those ventilated, 20 to 60 percent will die. However, this can vary from country to country due to various reasons. For example, in one study, 71.6% were hospitalized in the Kingdom of Saudi Arabia, and 4.6% were admitted to intensive care.

The rest of those who are hospitalized (95%), are at risk of having long term sequelae. From the SARS CoV infection data, 50 per cent had changes consistent with inflammatory lung disease at 4 weeks, and at 15 years, 4.6% (SD 6.4%) had pulmonary fibrosis. Middle East Respiratory Syndrome (MERS) had typical lower lobe fibrotic changes in more than one-third of the patients. SARS CoV2 virus shares 79.5% sequence identity with SARS CoV and 50% with MERS CoV. The SARS CoV2 may also have similarities in the inflammatory response; emerging data shows that COVID 19 patients also have new interstitial lung disease changes and thromboembolic disease. These patients may have long term physiological disability such as exertional hypoxia, breathlessness, reduction in static and dynamic lung volumes and diffusion factors.

There is currently no data available to predict who is at risk of developing long term chronic thromboembolic disease and interstitial lung disease. More importantly, there are no data available on the pathological changes of inflammatory lung disease. Pathologically classifying the disease may have a significant impact on the choice of the treatment for these patients who otherwise have the potential to be disabled lifelong. With appropriate phenotyping, appropriate risk reduction strategies and targeted therapies can be considered. Furthermore, studying biomarkers that could potentially identify those at-risk patients from very early on can provide an opportunity to start on the treatment very early on in the natural course of the disease history.