Incidence and risk factors for SARS-CoV-2 infection in patients with lupus nephritis

Background: Patients with lupus nephritis (LN) are known to be at higher risk for severe infections due to both an underlying immune dysfunction and as a consequence of immunosuppressive therapy (IS). We sought to investigate the impact of COVID-19 pandemic in patients with LN. Methods: A total of 95 patients with LN actively monitored in our department between 26th February 2020, when the first case of COVID-19 was diagnosed in Romania, and 1st May 2021 were included in the study. Demographics, comorbidities, clinical and laboratory characteristics, current IS therapy, COVID-19 symptoms and outcome were collected. A COVID-19 diagnosis was made if clinical symptoms were accompanied by a positive SARS-CoV-2 PCR. Results: Fifteen patients (15.8%) were diagnosed with COVID-19 at a median 279 days (IQR:218-341) since the first case was diagnosed in Romania. The majority of infections were mild (73.3%), moderate infections being encountered in the remaining patients (26.7%), while none has developed a severe infection. The most common (53.3%) and fever (46.7%). Overall, 40% of patients were hospitalized for a median of 11.5 days (IQR:3.75-14). Of these, 2 patients needed supplemental oxygen and 1 patient non-invasive ventilation. There were no COVID-19-related deaths during the study period. Of the clinical variables associated with infection development, fewer patients with COVID-19 were on hydroxychloroquine (66.7% vs. 89%, p=0.04) or were on clinical remission during the study period (40% vs. 67.5%, p=0.04), while the median maintenance oral corticosteroid dose was significantly higher in those with SARS-CoV-2 infection compared to those without [16 mg (IQR:7-21) vs. 6 mg (IQR:4-10), p=0.007]. In multivariate Cox regression analysis, use of hydroxychloroquine (HR, 0.23;95%CI, 0.04-1.26) and oral corticosteroid dose (HR, 1.11;95%CI, 1.01-1.22) remained the most important predictors of COVID-19. Conclusions: The burden of SARS-CoV-2 infection in patients with LN seems to be low. Use of hydroxychloroquine seems to be associated with a lower risk for COVID-19, while from different immunosuppressive agents corticosteroid dose was identified as an independent risk factor for infection development.