Background: The Covid-19 pandemic has enormously impacted the delivery of clinical healthcare and hospital management practices in most of the hospitals around the world for both Covid and no-Covid patients . In this context, it is extremely important to assess whether the clinical management of no-Covid cases has not seriously been compromised during the first epidemic outbreak . Among no-Covid cases, patients with acute myocardial infarction (AMI) and stroke need non-deferrable emergency care and are the natural candidates as no-Covid patients to be studied . Preliminary evidence suggests that i) the time from onset of symptoms to emergency department (ED) presentation has increased in Covid-19 times as well 30-day mortality during the pandemic has been higher . We aimed to complement this evidence assessing if the additional stress due to the high inflow of Covid-19 patients at hospital level has modified AMI and Stroke admission criteria and related mortality rates in a causal inference framework .
Methods: To study the impact of Covid pandemic on mortality rates for AMI and Stroke we adopt two quasi-experimental approaches, regression-discontinuity design (RDD) and difference-in-regression-discontinuity (DRD) designs by which we identify the plausible causal effect on mortality of the Covid-19-related hospital stress due to the introduction of State of Emergency restrictions . Findings: We check the causal effect of the Covid-19 pandemic on mortality rates of AMI and stroke over several time-windows of 15-days around the implementation date of the State of Emergency restrictions for COVID-19 (March , 9th). Despite the potential adverse effect on expected mortality due to a longer time to hospitalization, the AMI and Stroke mortality rates are overall not statistically different from the one observed in the control group . The obtained results provided by RDD and DRD models are robust also when we account for seasonality and unobserved factors . Interpretation: In a quasi-experimental setting we assessed the causal impact of the hospital and staff extra-burden generated by the first wave of Covid-19 patients on mortality rates of no-Covid non-deferrable urgent cases (AMI and Stroke) hospitalized at Spedali Civili of Brescia, one of the most hit provinces in Italy by Covid-19 during March and May 2020 . We find a non-statistically significant impact on mortality rates for AMI and Stroke patients providing evidence of the hospital ability to manage -with the implementation of a double track organization- the simultaneously delivery of high quality cares to both Covid and no-Covid patients . Availability of similar data for the regional context as a whole is needed to further substantiate the findings and explore existing differences in efficacy of different managerial settings implemented in Lombardy hospitals.