Higher testing coverage is associated with lower COVID-19 mortality rate: insights from Italian regions

Different COVID-19 testing approaches have been implemented among Italian regions, reflected in heterogeneous testing rates. We analysed the number COVID-19-related deaths in relation to the number of tests performed among the most hit Italian regions. We showed that regions with the highest number of tests performed (Veneto and Toscana) had the lowest 30-day crude mortality rate per 100,000 inhabitants. In addition, an inverse association between crude mortality rates and tests performed (mortality rate ratio for unit increase in tests per 1,000 inhabitants: 0.92; 95% CI 0.89-0.94) was observed. Early identification and isolation of active cases (including asymptomatic or mildly symptomatic subjects) could have had an important effect in lowering COVID-19 mortality.