Detection frequency and duration of lupus anticoagulant circulation in COVID-19 patients

The aim of the work was to determine frequency of lupus anticoagulant (LA) detection in patients at various degrees of COVID-19 severity as well as duration of LA circulation after the infectious disease. The study included 103 patients with COVID-19. The patients were observed during the hospital care and in ambulance, if required. The patients were admitted to the departments of infectious diseases arranged at the V.I.Kulakov National Medical Research Center for Obstetrics, Gynecology, and F.I. Inozemtsev City Clinical Hospital. Treatment schedules and stratification of the patients by clinical severity was carried out in accordance with Interim Guidelines issued by the Ministry of Health of the Russian Federation for the prevention, diagnosis and treatment of new coronavirus infection (version 9). The following groups were formed: mild (n = 27), moderate (n = 55) and severe (n = 20). The patients were tested for LA positivity in the course of disease: on the day of starting medical care (with outpatient observation), or on the day of hospitalization; repeated tests were made before discharge (inpatients), and later, 1-2 months and 7 months after recovery. Lupus anticoagulant was determined by two independent tests (dRVVT and SCT), i.e., as a screening test and a confirmation test. At initial examination, LA was found in 50 patients (49%). The effect of LA in 98% of cases was observed with dRVVT test, as an increase of normalized ratio (NR). The maximum median value of NR was 1.54 (0.97: 2.1) was revealed in patients with severe course of COVID-19 (p < 0.0001) compared with other groups and correlated with severity of the infectious process (r = 0.491, p < 0.0001). In mild cases of COVID-19, LA was detected less often (4 cases, 14.8%) than in moderate severity cases (27, 49.1%), and severe patients (19, 95%) (p < 0.05). Re-examinations of the patients before discharge from the hospital and 1-2 months later revealed high frequency of LA (p < 0.05). However, no LA-positive test was found 7 months after discharge. In patients with COVID-19, high frequency of circulating LA was registered, depending on severity of the infectious process. In addition, we have first shown that persistence of the circulating LA over post-infectious period does not exceed 7 months.