(1) Objectives: To describe the clinical characteristics and clinical course of hospitalized patients with COVID-19 and autoimmune diseases (ADs) compared to the general population. (2) Methods: We used information available in the nationwide Spanish SEMI-COVID-19 Registry, which retrospectively compiles data from the first admission of adult patients with COVID-19. We selected all patients with ADs included in the registry and compared them to the remaining patients. The primary outcome was all-cause mortality during admission, readmission, and subsequent admissions, and secondary outcomes were a composite outcome including the need for intensive care unit (ICU) admission, invasive and non-invasive mechanical ventilation (MV), or death, as well as in-hospital complications. (3) Results: A total of 13,940 patients diagnosed with COVID-19 were included, of which 362 (2.6%) had an AD. Patients with ADs were older, more likely to be female, and had greater comorbidity. On the multivariate logistic regression analysis, which involved the inverse propensity score weighting method, AD as a whole was not associated with an increased risk of any of the outcome variables. Habitual treatment with corticosteroids (CSs), age, Barthel Index score, and comorbidity were associated with poor outcomes. Biological disease-modifying anti-rheumatic drugs (bDMARDs) were associated with a decrease in mortality in patients with AD. (4) Conclusions: The analysis of the SEMI-COVID-19 Registry shows that ADs do not lead to a different prognosis, measured by mortality, complications, or the composite outcome. Considered individually, it seems that some diseases entail a different prognosis than that of the general population. Immunosuppressive/immunoregulatory treatments (IST) prior to admission had variable effects.

The coronavirus disease of 2019 (COVID-19) has been a cause of significant morbidity and mortality worldwide. Among the short- and long-term consequences of COVID-19, myocarditis is a disease to be taken into consideration. Myocarditis, in general, is related to a poor prognosis. However, the epidemiology and prognosis of myocarditis related to COVID-19 are currently unknown. While vaccination against COVID-19 is of great benefit at a public health level, the risk of myocarditis should be considered in the context of the global benefits of vaccination. In this narrative review, we will summarize the etiopathogenic bases, the epidemiology, the clinical manifestations, the course, diagnosis, prognosis, and the treatment of myocarditis related to SARS-CoV-2, as well as myocarditis secondary to mRNA vaccines.

The therapeutic management and short-term consequences of the coronavirus disease 2019 (COVID-19) are well known. However, COVID-19 post-acute sequelae are less known and represent a public health problem worldwide. Patients with COVID-19 who present post-acute sequelae may display immune dysregulation, a procoagulant state, and persistent microvascular endotheliopathy that could trigger microvascular thrombosis. These elements have also been implicated in the physiopathology of postural orthostatic tachycardia syndrome, a frequent sequela in post-COVID-19 patients. These mechanisms, directly associated with post-acute sequelae, might determine the thrombotic consequences of COVID-19 and the need for early anticoagulation therapy. In this context, heparin has several potential benefits, including immunomodulatory, anticoagulant, antiviral, pro-endothelial, and vascular effects, that could be helpful in the treatment of COVID-19 post-acute sequelae. In this article, we review the evidence surrounding the post-acute sequelae of COVID-19 and the potential benefits of the use of heparin, with a special focus on the treatment of postural orthostatic tachycardia syndrome.