COVID-19 and rheumatic autoimmune systemic diseases: report of a large Italian patients series.

Covid-19 infection poses a serious challenge for immune-compromised patients with inflammatory autoimmune systemic diseases. We investigated the clinical-epidemiological findings of 1641 autoimmune systemic disease Italian patients during the Covid-19 pandemic. This observational multicenter study included 1641 unselected patients with autoimmune systemic diseases from three Italian geographical areas with different prevalence of Covid-19 [high in north (Emilia Romagna), medium in central (Tuscany), and low in south (Calabria)] by means of telephone 6-week survey. Covid-19 was classified as (1) definite diagnosis of Covid-19 disease: presence of symptomatic Covid-19 infection, confirmed by positive oral/nasopharyngeal swabs; (2) highly suspected Covid-19 disease: presence of highly suggestive symptoms, in absence of a swab test. A significantly higher prevalence of patients with definite diagnosis of Covid-19 disease, or with highly suspected Covid-19 disease, or both the conditions together, was observed in the whole autoimmune systemic disease series, compared to "Italian general population" (p = .030, p = .001, p = .000, respectively); and for definite + highly suspected diagnosis of Covid-19 disease, in patients with autoimmune systemic diseases of the three regions (p = .000, for all comparisons with the respective regional general population). Moreover, significantly higher prevalence of definite + highly suspected diagnosis of Covid-19 disease was found either in patients with various "connective tissue diseases" compared to "inflammatory arthritis group" (p < .000), or in patients without ongoing conventional synthetic disease-modifying anti-rheumatic drugs treatments (p = .011). The finding of a higher prevalence of Covid-19 in patients with autoimmune systemic diseases is particularly important, suggesting the need to develop valuable prevention/management strategies, and stimulates in-depth investigations to verify the possible interactions between Covid-19 infection and impaired immune-system of autoimmune systemic diseases. Key Points • Significantly higher prevalence of Covid-19 is observed in a large series of patients with autoimmune systemic diseases compared to the Italian general population, mainly due to patients' increased susceptibility to infections and favored by the high exposure to the virus at medical facilities before the restriction measures on individual movement. • The actual prevalence of Covid-19 in autoimmune systemic diseases may be underestimated, possibly due to the wide clinical overlapping between the two conditions, the generally mild Covid-19 disease manifestations, and the limited availability of virological testing. • Patients with "connective tissue diseases" show a significantly higher prevalence of Covid-19, possibly due to deeper immune-system impairment, with respect to "inflammatory arthritis group". • Covid-19 is more frequent in the subgroup of autoimmune systemic diseases patients without ongoing conventional synthetic disease-modifying anti-rheumatic drugs, mainly hydroxyl-chloroquine and methotrexate, which might play some protective role against the most harmful manifestations of Covid-19.