Objective. In December 2019, an outbreak of unprecedented spread, later known as COVID-19, has taken the world by storm. Pre-existing metabolic disorders have been reported to be high-risk factors for severe COVID-19. We explored associations between sever COVID-19 outcomes and diabetes across 38 countries of the Organization for Economic Cooperation and Development (OECD). Methods. This was an ecological study that used freely accessible data from OECD and the World Health Organization databases. Outcome variables were case-fatality rate (CFR) and number of years of healthy life lost due to COVID-19 per 100,000 (YLLs/100,000). CFR was calculated based on cumulative COVID-19 cases and deaths as of 31 December 2020. Pearson’s correlation analysis was carried out to determine the correlates of COVID-19 CFR and YLLs; thereafter, ecological regression analysis was performed to identify the predictors of COVID-19 CFR and YLLs. Results. Mean population was 35,875,100 (±9,641,900) inhabitants. There were 1,559,488 (±699,285) COVID-19 cases reported and 43,579.5 (±19,055) deaths, for a COVID-19 CFR of 2.1 (0.2)% and COVID-19 YLLs of 566.8 (±91.5)/100,000 population. Overweight and obese population rate was 60.1 (±3.7)%, and overall diabetes prevalence rate was 6.9 (±0.4)%. Pearson correlation analysis showed that COVID-19 CFR was inversely correlated with country’s “high education completion rate” (rho = -0.41; p < 0.009), GDP per capita (rho = -0.47; p = 0.013), the ratio nurses/10,000 (rho = -0.36; p = 0.045), and positively correlated with diabetes prevalence (rho = 0.48; p = 0.003). On the other hand, COVID-19 YLLs were inversely correlated with elderly population rate (rho = 0.47; p = 0.003), and positively with diabetes prevalence rate (rho = -0.51; p = 0.011). Furthermore, the bivariate regression analysis showed that diabetes prevalence was positively associated with both COVID-19 CFR (beta = 1.01(0.3), 95%CI: 0.38–1.63; p = 0.002) and COVID-19 YLLs (beta = 8.28(3.5), 95%CI: 2.07–14.40; p = 0.010). Conclusion. Findings from this study tend to confirm that diabetes is a high-risk factor for severe COVID-19 outcomes at country level, disease mortality in particular.