BACKGROUND: Patients with coronavirus disease-2019 (COVID-19) with preexisting diabetes and cardiovascular metabolic diseases have higher fatality rate. The circulation of new variants with emerging clinical characteristics requires more studies focusing the impact of preexisting health conditions on outcome of COVID-19 accurately. AIMS: Main aim of this study was to investigate the impact of diabetes and cardiovascular disease (CVD) on disease prognosis and severe health outcomes among patients with COVID-19. METHODS: A retrospective study was performed on 799 patients with COVID-19 during December 10, 2020, to February 10, 2020 in Bangladesh. Logistic regression analysis was performed for age, sex, diabetes, CVD and symptoms on fatality. Kaplan-Meier survival analysis was conducted to predict the survival rate. RESULTS: Fatality was detected in 40% (318 of 799) patients with COVID-19. Among 318 fatalities, 90.6% were detected in patients with CVD and 74.5% in patients with diabetes. Case fatality rate was highest in patients with COVID-19, CVD and diabetes (94, 184 of 195). Fever (91%) and dry cough (71%) were the most frequent symptoms. CVD (42.2%), diabetes (32.7%) and obesity (18%) were prevalent. The highest odds of risk was detected in patients with COVID-19, CVD and diabetes (OR: 6.98, 95% CI, 4.21 to 7.34). Female patients had the highest survival rate. CONCLUSIONS: In this study, 318 fatality was seen in 799 patients with COVID-19. The highest odds of fatality risk was detected in patients with COVID-19, CVD and diabetes. The risk increased many folds when CVD and diabetes coexisted in patients.