COVID-19 severity and risk factors in Iranian patients with rheumatic diseases

Since the beginning of COVID-19 pandemic, there was a concern whether patients with rheumatic diseases are at increased risk of severe COVID-19 in terms of the multi-system involvement, underlying comorbidities, and anti-rheumatic medications. We intended to evaluate the severity and mortality of COVID-19 in these patients, as well as the demographic, laboratory, and clinical risk factors associated with the disease. In patients with plasma chane reaction positive COVID-19 admitted to the hospital, laboratory and clinical measures after hospitalization and severity measures such as length of hospitalization, hospitalization in the intensive care unit, and mortality were compared between patients with and matched patients without a history of rheumatic disease. Moreover, risk factors associated with COVID-19 mortality in the case group were calculated by odds ratio (OR). We found no statistically significant difference in COVID-19 severity between the two groups (mortality rate of 22% in case and 25% in control groups, P-value = 0.83). Except for platelet markers, which were considerably greater in the case group despite not being related with the severity of the illness, the available laboratory measurements did not vary between these groups. In addition, we showed that age over 65 years (OR = 4.06), lactic dehydrogenase level, percentage of lung involvement and ischemic heart disease (OR = 6.24) were associated with poorer outcome in the patients with rheumatic diseases. Hence, we found that usage of conventional synthetic disease modifying anti-rheumatic drugs (OR = 2.3, P-value = 0.48) or daily treatment dose of prednisolone >10 mg/d (OR = 1.04) were not associated with COVID-19 mortality. Although the patients with rheumatic disease may be at increased risk of developing a COVID-19 infection, they do not experience more severe disease.