Coronavirus Disease 2019 (Covid-19) is affecting life all over the world with an increasing number of infected individuals and fatality. Certain individuals are at a higher risk for severe illness if they become infected. This study aims to identify the risk of progression of COVID-19 symptoms for patients with underlying diseases residing in the National Capital Region, Philippines. The longer the patient stays in the hospital, the higher the risk that the symptoms will progress from mild to severe illness. Descriptive statistics were used to categorize quantitative data, Correlation to identify significant relationships between variables, ANOVA to determine the significant difference among all the factors, a Tukey test was conducted to identify which of the specific pairs are statistically significant, and multiple linear regression to obtain significant factors that could affect the number of days that a patient with underlying diseases experiences mild to severe symptoms, as well as the number of days that a patient with severe symptoms to be transferred to the medical ward. Lastly, Risk assessment with the use of Kepner Tregoe (KT) Analysis was utilized. Findings reveal that factors age, blood type group, gender, vitamin intake, sleeping hours, and smoking have a significant difference between the duration of Mild and Severe infection. The length of having symptoms is directly proportional to the whole duration of the infection. Furthermore, Comorbidity Cancer with Chronic Kidney Disease and Type II Diabetes has the longest duration of severe infection among all the underlying disease and comorbidity.