Risk factors for infection, predictors of severe disease and antibody response to COVID-19 in patients with rheumatic diseases in Portugal - a multicentre, nationwide study (preprint)

In order to identify risk factors for SARS-CoV-2 infection as well as for severe/critical COVID-19 in rheumatic and musculoskeletal diseases (RMDs) patients, we conducted a multicentre observational nationwide study of adult patients prospectively-followed in the Rheumatic Diseases Portuguese Register - Reuma.pt - during the first 6 months of the pandemic. We further evaluated the development of IgG antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 in patients with RMDs. We used multivariate logistic regression to compare patients with COVID-19 (COVID-19+) with those who did not develop the disease (COVID-19-) and patients with mild/moderate disease with those exhibiting severe/critical COVID-19. COVID-19+ patients were asked to collect a blood sample for IgG testing [≥] 3 months after infection and results were compared with age-, sex- and sampling date-matched controls. Overall, 179 cases of COVID-19 were registered in Reuma.pt in the period of interest (median age 55 (IQR 20); 76.5% females) in a total of 6404 registered appointments. We found that patients treated with TNF inhibitors had reduced odds of infection (OR=0.16, 95%CI 0.10-0.26, p<0.001), severe disease (OR 0.11, 95%CI 0.01-0.84, p=0.010) and seroconversion rates (OR 0.13, 95%CI 0.02-0.91, p=0.040). Tocilizumab was also associated with a reduced risk of COVID-19 (OR 0.15, 95%CI 0.05-0.41, p<0.001). Older age, major comorbidities (diabetes, hypertension, obesity, cardiovascular disease, chronic pulmonary and kidney disease) and rituximab were associated with an increased risk of infection and worse prognosis, in line with previous reports. Importantly, most patients with inflammatory RMDs (86.2%) were able to develop a robust antibody response after SARS-CoV-2 infection, which was linked with disease severity.

Vitamin D-related Polymorphisms and Vitamin D Levels as Risk Biomarkers of COVID-19 Infection Severity (preprint)

Background: Vitamin D is a fundamental regulator of host defences by activating genes related to innate and adaptive immunity. Previous research shows a correlation between the levels of vitamin D in patients infected with SARS-CoV-2 and the degree of disease severity. This work investigates the impact of the genetic background related to vitamin D pathways on COVID-19 severity. For the first time, the Portuguese population was characterized regarding the prevalence of high impact variants in genes associated with the vitamin D pathways. Methods: This study enrolled 517 patients admitted to two tertiary Portuguese hospitals. The serum concentration of 25 (OH)D, was measured in the hospital at the time of patient admission. Genetic variants, 18 variants, in the genes AMDHD1, CYP2R1, CYP24A1, DHCR7, GC, SEC23A, and VDR were analysed. Results: The results show that polymorphisms in the vitamin D binding protein encoded by the GC gene are related to the infection severity (p = 0.005). There is an association between vitamin D polygenic risk score and the serum concentration of 25 (OH)D (p = 0.042). There is an association between 25 (OH)D levels and the survival and fatal outcomes (p = 1.5e-4). The Portuguese population has a higher prevalence of the DHCR7 RS12785878 variant when compared with its prevalence in the European population (19% versus 10%).Conclusion: This study shows a genetic susceptibility for vitamin D deficiency that might explain higher severity degrees in COVID-19 patients. These results reinforce the relevance of personalized strategies in the context of viral diseases.

Vitamin D-related polymorphisms and vitamin D levels as risk biomarkers of COVID-19 infection severity (preprint)

Background: Vitamin D is a fundamental regulator of host defences by activating genes related to innate and adaptive immunity. Previous research shows a correlation between the levels of vitamin D in patients infected with SARS-CoV-2 and the degree of disease severity. This work investigates the impact of the genetic background related to vitamin D pathways on COVID-19 severity. For the first time, the Portuguese population was characterized regarding the prevalence of high impact variants in genes associated with the vitamin D pathways. Methods: This study enrolled 517 patients admitted to two tertiary Portuguese hospitals. The serum concentration of 25 (OH)D, was measured in the hospital at the time of patient admission. Genetic variants, 18 variants, in the genes AMDHD1, CYP2R1, CYP24A1, DHCR7, GC, SEC23A, and VDR were analysed. Results: The results show that polymorphisms in the vitamin D binding protein encoded by the GC gene are related to the infection severity (p = 0.005). There is an association between vitamin D polygenic risk score and the serum concentration of 25 (OH)D (p = 0.042). There is an association between 25 (OH)D levels and the survival and fatal outcomes (p = 1.5e-4). The Portuguese population has a higher prevalence of the DHCR7 RS12785878 variant when compared with its prevalence in the European population (19% versus 10%). Conclusion: This study shows a genetic susceptibility for vitamin D deficiency that might explain higher severity degrees in COVID-19 patients. These results reinforce the relevance of personalized strategies in the context of viral diseases.